Exhibit 2.1



                               EXCHANGE AGREEMENT
                               ------------------


         THIS EXCHANGE AGREEMENT (the "Agreement") is made as of April 12, 2000,
by and among MAXYGEN, INC., a Delaware corporation ("Maxygen"), MAXYGEN HOLDINGS
LTD., a Cayman Islands corporation ("Holdings"), all of whose capital stock is
owned directly by Maxygen, PROFOUND PHARMA A/S, a Danish corporation
("ProFound"), and the shareholders of ProFound.

                                    RECITALS
                                    --------

         A. The Boards of Directors of Maxygen, Holdings and ProFound have
determined that it is advisable and for the respective benefit of Maxygen,
Holdings and ProFound, and their respective securityholders and in their
long-term strategic interests, to combine their businesses in order to combine
their complementary capabilities, assets and human resources to develop
protein-based drugs that address market needs for improved biopharmaceuticals,
and have approved this Agreement and authorized the transactions contemplated
hereby on the terms and subject to the conditions of this Agreement.

         B. Pursuant to the terms of this Agreement: (i) the outstanding shares
of Common Stock of ProFound shall be exchanged for newly issued shares of Common
Stock of Maxygen; (ii) some or all of the warrants to subscribe for shares of
Common Stock of ProFound shall be exchanged for options to purchase shares of
Common Stock of Maxygen and (iii) the ProFound securities referenced in (i) and
(ii) above shall subsequently be exchanged by Maxygen for shares of Common Stock
of Holdings.

         C. The parties intend that for tax purposes the exchanges provided for
in Recital B shall (i) be approved by the Danish tax authorities as tax deferred
reorganizations within the meaning of Section 13 of the Danish Act on Taxation
of Capital Gains on Shares (aktieavancebeskatningsloven) and (ii) not qualify as
"tax free" reorganizations within the meaning of Section 368 of the United
States Internal Revenue Code.

         D. The ProFound Securityholders (as defined below) own all of the
outstanding capital stock of ProFound and all securities or other instruments
convertible into or exercisable for capital stock of ProFound.


THE PARTIES AGREE AS FOLLOWS:

1.       DEFINITIONS
         -----------

         For purposes of this Agreement, the following terms shall have the
meanings specified or referred to in this Section 1:

         "Accounts Receivable"-- shall mean all accounts receivable reflected on
          -------------------
the Financial Statements or accounts receivable ledger of ProFound.

         "Agreement"-- shall mean this Exchange Agreement.
          ---------

         "Alternative Acquisition"-- as defined in Section 7.8.
          -----------------------

         "BankInvest I" -- shall mean Bankforeningernes
          ------------
Erhvervsudviklingsforening BankInvest Biomedicinsk Udvikling.

         "BankInvest II" -- shall mean Aktieselskabet BI Biomedicinsk Udvikling
          -------------

         "Business Day"-- shall mean any day, Monday through Friday, on which
          ------------
U.S. federally chartered banks are open for business in San Francisco,
California and Danish banks are open for business in Copenhagen, Denmark.

         "CCL"-- shall mean the Cayman Islands Companies Law (1998).
          ---

         "Claim"-- as defined in Section 12.4.
          -----

         "Closing"-- as defined in Section 2.3(a).
          -------

         "Closing Date"-- shall mean the date and time as of which the Closing
          ------------
actually takes place.

          "Code"-- shall mean the United States Internal Revenue Code.
           ----

         "Commission"-- shall mean the United States Securities and Exchange
          ----------
Commission.

         "Confidentiality Agreement"-- shall mean the Confidentiality Agreement,
          -------------------------
dated February 7, 2000, between Maxygen and ProFound.

         "Contract"-- shall mean any agreement, contract, obligation, promise,
          --------
commitment or undertaking of any kind (whether written or oral and whether
express or implied), other than those that have been terminated.

                                       2


         "DCA"-- shall mean the Danish Companies Act, as amended.
          ---

         "DGCL"-- shall mean the Delaware General Corporation Law, as amended.
          ----

         "Employee Benefit Plan"-- shall mean any plan, policy, program,
          ---------------------
practice, agreement, understanding or arrangement (whether written or oral)
providing compensation or other benefits (other than ordinary cash compensation)
to any current or former director, officer, employee or consultant (or to any
dependent or beneficiary thereof), of ProFound, which are now, or were since
inception of ProFound, maintained by ProFound, or under which ProFound has or
could have any obligation or liability, whether actual or contingent, including,
without limitation, all incentive, bonus, deferred compensation, vacation,
holiday, cafeteria, medical, disability, stock purchase, stock option, warrant,
stock appreciation, phantom stock, restricted stock or other stock-based
compensation plans, policies, programs, practices or arrangements.

         "Employment Agreements"-- as defined in Section 7.9.
          ---------------------

         "Encumbrance"-- shall mean any mortgage, charge, claim, community
          -----------
property interest, equitable interest, lien, option, pledge, security interest,
right of first refusal or restriction of any kind, including any restriction on
use, voting, transfer, receipt of income or exercise of any other attribute of
ownership; and the verb "Encumber" shall be construed accordingly.

         "Environmental Claim"-- shall mean any accusation, allegation, notice
          -------------------
of violation, action, claim, Encumbrance, Lien, demand, abatement or other Order
or direction (conditional or otherwise) by any Governmental Authority or any
Person for personal injury (including sickness, disease or death), tangible or
intangible property damage, damage to the environment, nuisance, pollution,
contamination or other adverse effects on the environment, or for fines,
penalties or restrictions resulting from or based upon (i) the existence, or the
continuation of the existence, of a Release (including, without limitation,
sudden or non-sudden accidental or non-accidental Releases) of, or exposure to,
any Hazardous Material or other substance, clinical, material, pollutant,
contaminant, odor, audible noise, or other Release in, into or onto the
environment (including, without limitation, the air, soil, surface water or
groundwater) at, in, by, from or related to the Facilities or any activities
conducted thereon; (ii) the environmental aspects of the transportation,
storage, treatment or disposal of Hazardous Materials in connection with the
operation of the Facilities; or (iii) the violation, or alleged violation, of
any Environmental Laws, Orders or Governmental Permits of or from any
Governmental Authority relating to environmental matters connected with the
Facilities.

         "Environmental, Health and Safety Liabilities"-- shall mean any cost,
          --------------------------------------------
damage, expense, liability, obligation or other responsibility arising from or
under any Environmental Law, as well as any liability for torts and damages
according to general

                                       3


Danish rules, regulations and ordinary principles, including case law, or
Occupational Safety and Health Law and consisting of or relating to: (a) any
environmental, health or safety matter or condition (including on-site or off-
site contamination, generation, handling and disposal of Hazardous Materials,
occupational safety and health, and regulation of chemical and Hazardous
Materials); (b) fines, penalties, judgments, awards, settlements, legal or
administrative proceedings, damages, losses, litigation, including civil and
criminal claims, demands and responses, investigative, remedial, response or
inspection costs and expenses arising under Environmental Law or Occupational
Safety and Health Law; (c) financial responsibility under Environmental Law or
Occupational Safety and Health Law for cleanup costs or corrective action,
including any investigation, cleanup, removal, containment or other remediation
or response actions required by applicable Environmental Law or Occupational
Safety and Health Law and for any natural resource damages; or (d) any other
compliance, corrective, investigative or remedial measures required under
Environmental Law or Occupational Safety and Health Law.

         "Environmental Law"-- shall mean any Law concerning the environment, or
          -----------------
activities that might threaten or result in damage to the environment or human
health, or any Law that is concerned in whole or in part with the environment
and with protecting or improving the quality of the environment and human and
employee health and safety and includes, but is not limited to, the Danish
Environmental Protection Act, the Danish Soil Pollution Act, the Danish Act on
Chemical Substances and Products, the Danish Act on Environmental Gene
Technology, the Danish Act on Compensation for Environmental Damages, the Danish
Act on Working Environment, as such laws have been amended or supplemented, and
the regulations, statutory orders, local council waste by-laws, and other
binding by-laws and guidance and practice notes adopted under any of those laws.

         "Escrow Agent"-- as defined in Section 3.1.
          ------------

         "Escrow Agreement"-- as defined in Section 3.1.
          ----------------

         "Escrow Shares"-- as defined in Section 3.1.
          -------------

         "Exchange Act"-- shall mean the United States Securities Exchange Act
          ------------
of 1934, as amended, or any successor law.

         "Exchange Agent"-- as defined in Section 2.4(a).
          --------------

         "Exchanges"-- shall mean the Holdings Exchange and the Maxygen
          ---------
Exchange.

         "Expiration Date"-- as defined in Section 12.1(b).
          ---------------

         "Facilities"-- shall mean any real property, leaseholds or other
          ----------
interests currently or formerly owned or operated by ProFound, and any
buildings, plants, structures or

                                       4


equipment (including motor vehicles) currently or formerly owned or operated by
ProFound.

         "Founding Shareholders"-- shall mean Christian Karsten Hansen, Jan
          ---------------------
Moller Mikkelsen, Torben Halkier, Jens Sigurd Okkels, Anders Pedersen, Hans
Thalsgard Schambye, Knud Aunstrup, Claus Braestrup and Thue W. Schwartz.

         "GAAP"-- shall mean generally accepted Danish accounting principles
          ----
applied on a consistent basis.

         "Governmental Authority"-- shall mean any court, tribunal, authority,
          ----------------------
agency, commission, bureau, department, official or other instrumentality of the
United States, the European Union, Denmark, any other country or any provincial,
state, local, county, city or other political subdivision.

         "Governmental Permit"-- shall mean any license, franchise, permit or
          -------------------
other authorization of any Governmental Authority.

         "Hazardous Materials"-- shall mean any substance, material or waste
          -------------------
which is regulated by any Environmental Law, including but not limited to,
petroleum products, asbestos and polychlorinated biphenyls.

         "Holdings"-- as defined in the first paragraph of this Agreement.
          --------

         "Holdings Common Stock"-- shall mean the Common Stock of Holdings.
          ---------------------

         "Holdings Exchange"-- as defined in Section 2.2.
          -----------------

         "Intellectual Property"-- as defined in Section 4.21(a).
          ---------------------

         "Law"-- shall mean any Danish, European Union, other non-United States,
          ---
United States, state or local (including common law) statute, code, directive,
ordinance, rule, regulation or other requirement.

         "Lien"-- shall mean any lien, pledge, hypothecation, levy, mortgage,
          ----
deed of trust, security interest, claim, lease, charge, option, right of first
refusal, easement, or other real estate declaration, covenant, condition,
restriction or servitude, transfer restriction under any shareholder or similar
agreement, encumbrance or any other restriction or limitation whatsoever.

         "Lock-up Agreement"-- as defined in Section 7.12.
          -----------------

         "Losses"-- as defined in Section 12.2.
          ------

         "Maxygen"-- as defined in the first paragraph of this Agreement.
          -------

                                       5


         "Maxygen Common Stock"-- shall mean the Common Stock, $0.0001 par value
          --------------------
per share, of Maxygen.

         "Maxygen Disclosure Schedule"-- shall mean the disclosure schedule
          ---------------------------
delivered by Maxygen to ProFound concurrently with the execution and delivery of
this Agreement.

         "Maxygen Exchange"-- as defined in Section 2.1.
          ----------------

         "Maxygen Indemnitee"-- as defined in Section 12.2.
          ------------------

         "Maxygen Material Adverse Effect"-- shall mean an event that materially
          -------------------------------
and adversely affects the business, results of operation or financial condition
of Maxygen and its Subsidiaries taken as a whole; provided, however, that any
such effect resulting from (i) any change in economic or business conditions
generally affecting the biotechnology industry or (ii) any change in generally
accepted accounting principles or interpretations thereof generally affecting
the biotechnology industry or (iii) any reduction in the trading price of the
Maxygen Common Stock shall not be considered when determining if a Maxygen
Material Adverse Effect has occurred.

         "Maxygen Reports"-- as defined in Section 6.3(a).
          ---------------

         "Occupational Safety and Health Law"-- shall mean any legal or
          ----------------------------------
governmental requirement or obligation relating to safe and healthful working
conditions or to occupational safety and health hazards, whether governmental or
private (including those promulgated or sponsored by industry associations and
insurance companies), designed to provide safe and healthful working conditions.

         "Order"-- shall mean any order, consent, consent order, injunction,
          -----
judgment, decree, consent decree, ruling, writ, assessment or arbitration award.

         "Organizational Documents"-- shall mean: (a) the articles or
          ------------------------
certificate of incorporation, memorandum of association, articles of association
and the by-laws of a corporation; (b) the partnership agreement and any
statement of partnership of a general partnership; (c) the limited partnership
agreement and the certificate of limited partnership of a limited partnership;
(d) the articles or certificate of formation and operating agreement of a
limited liability company; (e) any charter, trust certificate or document or
similar document adopted or filed in connection with the creation, formation or
organization of a Person; and (f) any and all amendments to any of the
foregoing.

         "Person"-- shall mean any individual, corporation (including any
          ------
non-profit corporation), general or limited partnership, limited liability
company, joint venture, estate, trust, association, organization, labor union or
other entity or governmental body or Governmental Authority.

                                       6


         "Proceeding"-- shall mean any claim, action, investigation,
          ----------
arbitration, litigation or other judicial, administrative or regulatory
proceeding.

         "ProFound Common Stock"-- shall mean the Class A and Class B Common
          ---------------------
Stock of ProFound.

         "ProFound Disclosure Schedule"-- shall mean the disclosure schedule
          ----------------------------
delivered by ProFound to Maxygen and Holdings concurrently with the execution
and delivery of this Agreement.

         "ProFound Financial Statements"-- shall mean (i) the audited balance
          -----------------------------
sheet and statement of shareholders owning more than five percent of the share
capital of ProFound as of December 31, 1999 and the related income statement and
statement of cash flow for the year then ended, and (ii) the ProFound Interim
Financial Statements. The ProFound Financial Statements are included in Section
4.5 of the ProFound Disclosure Schedule.

         "ProFound Intellectual Property"-- as defined in Section 4.21(a).
          ------------------------------

         "ProFound Interim Financial Statements"-- shall mean the unaudited
          -------------------------------------
balance sheet and statement of shareholders owning more than five percent of the
share capital of ProFound as of February 29, 2000, and the related unaudited
income statement for the two months then ended.

         "ProFound Material Adverse Effect"-- shall mean any material adverse
          --------------------------------
change in the business, operations, properties, assets, liabilities, results of
operations, condition or prospects (financial or otherwise) of ProFound;
provided, however, that any such effect resulting from (i) any change in
economic or business conditions generally affecting the biotechnology industry
or (ii) any change in generally accepted accounting principles or
interpretations thereof generally affecting the biotechnology industry shall not
be considered when determining if a ProFound Material Adverse Effect has
occurred.

         "ProFound Registered Intellectual Property"-- as defined in Section
          -----------------------------------------
4.21(a).

         "ProFound Securities"-- shall mean the ProFound Common Stock and the
          -------------------
ProFound Warrants.

         "ProFound Securityholders"-- shall mean the holders of ProFound Common
          ------------------------
Stock and ProFound Warrants.

         "ProFound Shareholders" -- shall mean the holders of ProFound Common
          ---------------------
Stock.

         "ProFound Warrants"-- shall mean warrants to purchase shares of
          -----------------
ProFound Common Stock.

                                       7


         "Registered Intellectual Property"-- as defined in Section 4.21(a).
          --------------------------------

         "Related Person"-- as defined in Section 4.23.
          --------------

         "Release"-- shall mean any release, spill, effluent, emission, leaking,
          -------
pumping, injection, deposit, disposal, discharge, dispersal, leaching, or
migration into the indoor or outdoor environment of any Hazardous Material
through or in the air, soil, surface water or groundwater.

         "Remedial Action"-- shall mean all actions, including, without
          ---------------
limitation, any expenditures, required or voluntarily undertaken to (i) clean
up, remove, treat, or in any other way address any Hazardous Material or other
substance in the indoor or outdoor environment; (ii) prevent the Release or
threat of Release, or minimize the further Release of any Hazardous Material or
other substance so it does not migrate or endanger or threaten to endanger
public health or welfare of the indoor or outdoor environment; (iii) perform
pre-remedial studies and investigations or post-remedial monitoring and care; or
(iv) bring any Facility into compliance with all Environmental Laws and
Environmental Permits.

         "Representatives"-- shall mean officers, directors, employees, agents,
          ---------------
attorneys, accountants, advisors and representatives.

         "Returns"-- shall mean returns, reports and forms.
          -------

         "Securities Act"-- shall mean the United States Securities Act of 1933,
          --------------
as amended, or any successor law.

         "Securityholder Representative"-- as defined in Section 3.2(a).
          -----------------------------

         "Shareholders Agreement"-- shall mean the Shareholders Agreement dated
          ----------------------
April 28, 1999 among certain ProFound Securityholders.

         "Subsidiary"-- shall mean with respect to any Person, any corporation,
          ----------
joint venture, limited liability company, partnership, association or other
business entity of which 50% or more of the total voting power of stock or other
equity entitled to vote generally in the election of directors or managers or
equivalent Persons thereof is owned or controlled, directly or indirectly, by
such Person.

         "Tax Authority"-- shall mean the Danish, United States, and any state,
          -------------
local or foreign government or any agency or subdivision thereof.

         "Taxes"-- shall mean all taxes, charges, fees, customs, duties or other
          -----
assessments, however denominated, including all interest, penalties, additions
to tax or additional taxes that may become payable in respect thereof, imposed
by a Tax Authority, which shall

                                       8


include, without limitation, all income taxes, payroll and employee withholding
taxes, unemployment insurance, social security, sales and use taxes, excise
taxes, capital taxes, franchise taxes, gross receipt taxes, occupation taxes,
real and personal property taxes, value added taxes, stamp taxes, transfer
taxes, workers' compensation taxes, taxes relating to benefit plans and other
obligations of the same or similar nature.

         "Transaction Documents"-- means the agreements, documents or
          ---------------------
instruments executed and delivered by a party hereto as contemplated under this
Agreement.

2. THE EXCHANGES; CLOSING
   ----------------------

    2.1 THE MAXYGEN EXCHANGE
        --------------------

        (a) Upon the terms and subject to the conditions set forth in this
Agreement (including, without limitation, the last sentence of Section 2.1(e))
and in accordance with the DCA, at the Closing all of the ProFound
Securityholders (shall transfer and assign all of their respective right, title
and interest in and to all of their ProFound Securities to Maxygen in exchange
for shares of Maxygen Common Stock and options to purchase shares of Maxygen
Common Stock (collectively the "Maxygen Exchange") as provided in this Section
2.1.

        (b) Each share of Class A ProFound Common Stock shall be exchanged for
shares of Maxygen Common Stock. The total number of shares of Maxygen Common
Stock that Maxygen will issue under this Section 2.1(b) is 328,799 shares. The
number of shares of Maxygen Common Stock to be issued to each holder of Class A
ProFound Common Stock is set forth on Exhibit 2.1.

        (c) Each share of Class B ProFound Common Stock held by BankInvest I and
Novo Nordisk A/S shall be exchanged for shares of Maxygen Common Stock. The
total number of shares of Maxygen Common Stock that Maxygen will issue under
this Section 2.1(c) is 417,032 shares. The number of shares of Maxygen Common
Stock to be issued to each of BankInvest I and Novo Nordisk A/S is set forth on
Exhibit 2.1.

        (d) Each share of Class B ProFound Common Stock and each ProFound
Warrant to purchase shares of Class B ProFound Common Stock held by BankInvest
II shall be exchanged for shares of Maxygen Common Stock. The total number of
shares of Maxygen Common Stock that Maxygen will issue under this Section 2.1(d)
is 234,174 shares.

        (e) Subject to the last sentence of this Section 2.1(e), each ProFound
Warrant to purchase shares of Class A ProFound Common Stock shall be exchanged
for an option on substantially similar terms and conditions as those of such
ProFound Warrants, issued under the Maxygen International Stock Option Plan, to
purchase shares

                                       9


of Maxygen Common Stock. The total number of shares of Maxygen Common Stock to
be covered by all these "substitute Maxygen options" is 41,812. The exercise
price per share of Maxygen Common Stock under those substitute Maxygen options
will be $22.65. The number of shares of Maxygen Common Stock covered by the
substitute Maxygen options to be granted to each holder of a ProFound Warrant to
purchase shares of Class A ProFound Common Stock is set forth on Exhibit 2.1.
The substitute Maxygen options shall have the same vesting schedule as the
vesting schedule for the corresponding ProFound Warrant. In other words, the
present vesting schedule that applies to a ProFound Warrant shall be continued
for the Maxygen option that is substituted for that warrant. Notwithstanding the
foregoing, a given holder of a ProFound Warrant to purchase shares of Class A
ProFound Common Stock shall not be entitled to receive any substitute Maxygen
options unless he or she will be a continuing employee of ProFound after the
Closing and has delivered, before the Closing, the agreements required by
Section 9.9.

    2.2  THE HOLDINGS EXCHANGE
         ---------------------

         The parties acknowledge that, in accordance with the CCL and the DGCL,
immediately following the Maxygen Exchange, Maxygen intends to exchange the
ProFound Securities for 1,000 shares of Holdings Common Stock (the "Holdings
Exchange"). However, nothing in this Agreement shall require Maxygen to effect
the Holdings Exchange.

    2.3 THE CLOSING
        -----------

        (a) Unless this Agreement shall have been terminated and the
transactions herein contemplated shall have been abandoned pursuant to Section
11, and subject to the satisfaction or waiver of the conditions set forth in
Sections 9 and 10, the consummation of the Exchanges shall take place on or as
promptly as practicable (and in any event within two business days) after
satisfaction or waiver of the conditions set forth in Sections 9 and 10 at the
offices of Heller Ehrman White & McAuliffe LLP, 2500 Sand Hill Road, Suite 100,
Menlo Park, California 94025 (the "Closing"), unless another date, time or place
is agreed to in writing by ProFound and Maxygen.

        (b) As soon as practicable following the Closing, the parties hereto
shall cause the Exchanges to be memorialized by making all filings or recordings
required under the CCL, DCA and the DGCL.

        (c) At and after the Closing, the Exchanges will have the
effects set forth in this Agreement, and ProFound shall be a wholly owned
subsidiary of Holdings.

                                       10


    2.4 SURRENDER OF CERTIFICATES
        -------------------------

        (a) Exchange Agent. ChaseMellon Shareholders Services, L.L.C. shall act
            --------------
as exchange agent (the "Exchange Agent") for the Maxygen Exchange.

        (b) Common Stock and Options to Purchase Common Stock. Promptly after
            -------------------------------------------------
the Closing, Maxygen shall make available for exchange in accordance with
Section 2.1 the aggregate number of shares of Maxygen Common Stock and options
to purchase Maxygen Common Stock issuable pursuant to Section 2.1 in exchange
for the issued and outstanding ProFound Securities.

    2.5 EXCHANGE PROCEDURES
        -------------------

        (a) Surrender of Certificates. At the Closing, the ProFound
            -------------------------
 Shareholders shall deliver to the Exchange Agent (i) certificates representing
all of the ProFound Securities held by them, duly completed and validly
executed, (ii) documentary evidence of the due recordation in ProFound's share
register of Maxygen's (and then Holdings') full and unrestricted title to all of
the ProFound Securities held by them and (iii) such other documents as may be
required, whereupon each ProFound Shareholder shall be entitled to receive in
exchange therefor, subject to the escrow requirements of Section 3.1,
certificates evidencing the number of shares of Maxygen Common Stock to which
such ProFound Shareholder is entitled pursuant to Section 2.1.

        (b) No Further Ownership Rights in ProFound Securities. All shares of
            --------------------------------------------------
Maxygen Common Stock issued upon the surrender for exchange of shares of
ProFound Common Stock in accordance with the terms hereof and all Maxygen
Options issued upon surrender for exchange of ProFound Warrants shall be deemed
to have been issued in full satisfaction of all rights pertaining to such shares
of ProFound Common Stock and such ProFound Warrants.

        (c) Restrictive Legends. Certificates evidencing shares of Maxygen
            -------------------
Common Stock pursuant to this Agreement shall bear the

following legends:

             (i) All certificates shall bear a restrictive legend indicating
that the shares evidenced thereby cannot be transferred except in accordance
with the terms of the applicable Lock-Up Agreement.

             (ii) All certificates shall bear a restrictive legend indicating
that the shares evidenced thereby were not registered pursuant to the Securities
Act, including any restrictive legend required by, or useful to aid compliance
with, Regulations D and S adopted by the Commission thereunder.

                                       11


3.       ESCROW OF SHARES
         ----------------

    3.1  DELIVERY OF ESCROW SHARES
         -------------------------

         In lieu of delivering to the ProFound Shareholders certificates for the
full number of shares of Maxygen Common Stock provided for in Section 2.1, at
the Closing Maxygen shall deliver pursuant to the escrow agreement substantially
in the form attached hereto as Exhibit 3.1 (the "Escrow Agreement") 140,728
shares of Maxygen Common Stock (the "Escrow Shares") to Maxygen as escrow agent
(the "Escrow Agent"). The ProFound Shareholders acknowledge and agree that the
Escrow Shares shall severally and jointly secure the indemnification obligations
set forth in Section 12. The Escrow Shares shall be held by the Escrow Agent for
at least 18 months after the Closing (and any longer period as provided in the
Escrow Agreement) and shall be applied in accordance with the terms of the
Escrow Agreement.

    3.2 SECURITYHOLDER REPRESENTATIVE
        -----------------------------

        (a) Each ProFound Shareholder hereby irrevocably constitutes and
appoints, effective as of the Closing, Christian Karsten Hansen (together with
his permitted successors, the "Securityholder Representative"), as the true and
lawful agent and attorney-in-fact to enter into any agreement in connection with
the transactions contemplated by this Agreement and any transactions
contemplated by the Escrow Agreement, to exercise any or all of the powers,
authority and discretion conferred on him under any such agreement, to accept
delivery of and to submit for exchange and cancellation any ProFound Securities,
to waive any terms and conditions of any such agreement, to give and receive
notices on his behalf and to be his, her or its exclusive representative with
respect to any matter or Proceeding arising with respect to any transaction
contemplated by any such agreement, including, without limitation, the defense,
settlement or compromise of any Proceeding for which any Maxygen Indemnitee may
be entitled to indemnification, and to act as the "Purchaser Representative" for
any ProFound Shareholder who is not an "accredited investor" as that term is
defined in Rule 501 adopted by the Commission under the Securities Act in
connection with evaluating the merits and risks of investing in the Maxygen
securities to be issued in the Maxygen Exchange, and the Securityholder
Representative agrees to act as, and to undertake the duties and
responsibilities of, such agent and attorney-in-fact.

        (b) Maxygen and the other Maxygen Indemnitees shall be entitled to deal
exclusively with the Securityholder Representative on all matters contemplated
herein and in the Escrow Agreement, including on the matters indicated in
Sections 10 and 11 and on all matters relating to Section 12, and shall be
entitled to rely exclusively (without further evidence of any kind whatsoever)
on any document executed or purported to be executed on behalf of any ProFound
Shareholder by the Securityholder Representative, and on any

                                       12


other action taken or purported to be taken on behalf of any ProFound
Shareholder by the Securityholder Representative, as fully binding upon such
ProFound Shareholder.

        (c) The Securityholder Representative shall not be liable to anyone for
any action taken or not taken by him in good faith or for any mistake of fact or
law for anything that he may do or refrain from doing in connection with his
obligations under this Agreement and the Escrow Agreement (i) with the consent
of ProFound Shareholders who, as of the date of this Agreement, owned a majority
of the outstanding shares of ProFound Common Stock, or (ii) in the absence of
his own gross negligence or willful misconduct. Any action taken or not taken
pursuant to the advice of counsel shall be conclusive evidence of the absence of
gross negligence or willful misconduct. The ProFound Shareholders shall, jointly
and severally, indemnify and hold the Securityholder Representative harmless
from any and all liability and expenses that may arise out of any action taken
or omitted by him as Securityholder Representative in accordance with this
Agreement and the Escrow Agreement, except such liability and expense as may
result from the gross negligence or willful misconduct of the Securityholder
Representative.

        (d) The Securityholder Representative may rely and shall be protected in
relying or refraining from acting on any instrument reasonably believed to be
genuine and to have been signed or presented by the proper party or parties. The
Securityholder Representative shall not be liable for other parties' forgeries,
fraud or false representations.

        (e) The Securityholder Representative shall have the reasonable
assistance of Maxygen's, Holdings' and ProFound's officers and employees for
purposes of performing his duties and exercising his rights hereunder, provided
that the Securityholder Representative shall treat confidentially and not
disclose any nonpublic information from or about Maxygen, Holdings or ProFound
to anyone (except on a need to know basis to individuals who agree to treat such
information confidentially).

        (f) If the Securityholder Representative shall be unable or unwilling to
serve in such capacity, his successor shall be named by those Persons holding a
majority of the shares of ProFound Common Stock outstanding just before the
Closing, and such successor shall serve and exercise the powers of the
Securityholder Representative hereunder and under the Escrow Agreement. If for
any reason there is no Securityholder Representative at any time, all references
herein to the Securityholder Representative shall be deemed to refer to ProFound
Shareholders who hold a majority of the shares of ProFound Common Stock
outstanding just before the Closing.

        (g) The Securityholder Representative hereby represents and
warrants to the other ProFound Shareholders that: (i) he has such knowledge and
experience in financial and business matters that he is capable of evaluating
the merits and risks of the investment in the Maxygen securities to be issued in
the Maxygen Exchange and (ii) there

                                       13


is no material relationship between himself and Maxygen other than the matters
set forth in this Agreement relating to the Maxygen securities that he will
receive as a result of the transactions contemplated by this Agreement,
including possible receipt of a portion of the additional Maxygen options
described in Section 8.1 and the compensation and other benefits that he will
receive as an employee of ProFound after the Closing, whether under his
Employment Agreement referenced in Section 7.9 or otherwise.

4.       REPRESENTATIONS AND WARRANTIES CONCERNING PROFOUND
         --------------------------------------------------

         Except as set forth in the ProFound Disclosure Schedule by means of a
disclosure that references the specific representation and warranty which that
the exception is intended to modify, ProFound and the ProFound Shareholders
hereby represent and warrant to Maxygen and Holdings as follows:

    4.1 ORGANIZATION AND GOOD STANDING
        ------------------------------

        (a) Section 4.1 of the ProFound Disclosure Schedule contains a complete
and accurate list of the jurisdictions in which ProFound is authorized to do
business. ProFound is a corporation duly organized, validly existing and in good
standing under the laws of its jurisdiction of incorporation or formation, with
full corporate power and authority to conduct its business as it is now being
conducted and to own or use the assets and properties that it purports to own or
use. ProFound is duly qualified to do business as a foreign corporation and is
in good standing under the Laws of each state or other jurisdiction in which
either the ownership or use of the assets or properties owned or used by it, or
the nature of the activities conducted by it, requires such qualification,
except where the failure to be so qualified could not reasonably be expected to
have a ProFound Material Adverse Effect. ProFound does not have, and has never
had, any Subsidiaries.

        (b) ProFound has delivered to Maxygen correct and complete copies of the
Organizational Documents of ProFound.

    4.2 AUTHORITY; NO CONFLICT
        ----------------------

        (a) ProFound has the right, power, authority and capacity to execute and
deliver this Agreement and the Transaction Documents to which it is and will be
a party, to consummate the transactions contemplated hereby and thereby and to
perform its obligations under this Agreement and the Transaction Documents to
which it is and will become a party. This Agreement has been duly authorized and
approved, executed and delivered by ProFound and constitutes the legal, valid
and binding obligation of ProFound, enforceable against ProFound in accordance
with its terms. Upon the authorization and approval, execution and delivery by
ProFound of the Transaction Documents to which it is a party, such Transaction
Documents will constitute legal, valid

                                       14


and binding obligations of ProFound, enforceable against ProFound in accordance
with their respective terms.

        (b) Neither the execution and delivery of this Agreement or any
Transaction Document by ProFound nor the consummation or performance by ProFound
of the Maxygen Exchange or any of the other transactions contemplated hereby or
thereby will, directly or indirectly (with or without notice or lapse of time or
both):

             (i) contravene, conflict with or result in a violation or breach of
(A) any provision of any Organizational Document of ProFound, (B) any resolution
adopted by the board of directors or the shareholders of ProFound, (C) any Law
or any Order, award, decision, settlement or process to which ProFound or any of
the assets or properties owned or used by ProFound may be subject, or (D) any
Governmental Permit that is held by ProFound;

             (ii) result in a breach of or constitute a default, give rise to a
right of termination, cancellation or acceleration, create any entitlement to
any payment or benefit, or require the consent, authorization or approval of or
any notice to or filing with any Person under any material Contract to which
ProFound is a party or to which any of its or their assets or properties are
bound, or require the consent, authorization or approval of or any notice to or
filing with any Governmental Authority to which ProFound or any of its or their
assets or properties is subject; or

             (iii) result in the imposition or creation of any Encumbrance or
Lien upon or with respect to any of the assets or properties owned or used by
ProFound.

    4.3  CAPITALIZATION
         --------------

         The authorized, issued and outstanding equity securities of ProFound
consist solely of 633,459 shares of common stock, DK1 par value per share. Of
those shares, 175,000 shares are designated Class A Common Stock and 458,459
shares are designated Class B Common Stock. All of the outstanding shares of
ProFound Common Stock have been duly authorized and validly issued, are fully
paid and nonassessable and are owned, of record and beneficially, by the Persons
and in the amounts set forth in Section 4.3 of the ProFound Disclosure Schedule.
Warrants to purchase 34,245 shares of Class A Common Stock and 139,289 shares of
Class B Common Stock are issued and outstanding. All of the ProFound Warrants
have been duly authorized and validly issued and are owned, of record and
beneficially, by the Persons and in the amounts set forth in Section 4.3 of the
ProFound Disclosure Schedule. Section 4.3 of the ProFound Disclosure Schedule
sets forth all outstanding securities of ProFound, including but not limited to
all debt securities, ProFound Common Stock, ProFound Warrants, rights and all
other securities convertible or exercisable into or for, or exchangeable for,
capital stock. Except as set forth in Section 4.3 of the ProFound Disclosure
Schedule, there are no

                                       15


voting trusts or other Contracts or understandings to which ProFound or any
ProFound Securityholder is a party with respect to the transfer, voting or
registration of any ProFound Securities and there are no Contracts relating to
the issuance, sale or transfer of any equity securities or other securities of
ProFound. ProFound does not own or have any Contract to acquire any equity
securities or other securities of any Person or any, direct or indirect, equity
or ownership interest in any other business. No Person has any pre-emptive
rights, nor any right of first refusal, tag-along, drag along right or any
rights similar thereto with respect to any security of ProFound. All of the
ProFound Securities have been issued in compliance with all Danish securities
Laws.

    4.4  BOOKS AND RECORDS
         -----------------

         The books of account and other records of ProFound, all of which have
been furnished to Maxygen, are true, complete and correct in all material
respects. The minute books of ProFound contain true, accurate and complete
records of all meetings held of, and corporate action taken by, the
stockholders, the board of directors, and committees of the board of directors
of ProFound. The share registry of ProFound contains a true, complete and
correct record of all issuances, transfers and repurchases of all ProFound
Securities.

    4.5  FINANCIAL STATEMENTS
         --------------------

         The ProFound Financial Statements (i) have been prepared from the books
and records of ProFound in accordance with GAAP (except for the omission of
footnotes and cash flow statement from the ProFound Interim Financial
Statements), (ii) fully reflect all liabilities and contingent liabilities of
ProFound required to be reflected therein on such basis as at the dates thereof,
and (iii) fairly present the financial position of ProFound and the share
holdings of ProFound's more-than-five-percent stockholders as of the dates of
the balance sheets included in the ProFound Financial Statements and the results
of ProFound's operations and (in the case of the audited financial statements
included in the ProFound Financial Statements) cash flow for the periods
indicated.

    4.6  NO UNDISCLOSED LIABILITIES
         --------------------------

         ProFound does not have any liabilities or obligations of any nature
(whether known or unknown, absolute, accrued, contingent or otherwise, and
whether due or to become due), except for liabilities or obligations reflected
or reserved against in the ProFound Financial Statements and current liabilities
incurred in the ordinary course of business since the date of the balance sheet
included in the ProFound Interim Financial Statements, consistent with past
practices, which will not, individually or in the aggregate, have a ProFound
Material Adverse Effect.

                                       16


    4.7  NO MATERIAL ADVERSE CHANGE
         --------------------------

         Since December 31, 1999, there has not been any ProFound Material
Adverse Effect and no event has occurred or circumstance exists that could
reasonably be expected to result in a ProFound Material Adverse Effect.

    4.8 TAXES
        -----

        (a) ProFound has filed or caused to be filed with the appropriate Taxing
Authorities in a timely manner all Tax Returns required to be filed by it; (ii)
the information on such Returns is complete and accurate in all material
respects; (iii) ProFound has paid in full on a timely basis all Taxes or made
adequate provision in the Financial Statements for all Taxes (whether or not
shown on any Return) required to be paid by them; (iv) there are no Encumbrances
or Liens for Taxes upon the assets or properties of ProFound other than for
Taxes not yet due and payable; (v) no deficiencies for Taxes have been claimed,
proposed, or assessed by any Tax Authority or other Governmental Authority with
respect to ProFound, and (vi) there are no pending or, to ProFound's knowledge,
threatened audits, investigations or claims for or relating to any liability in
respect of Taxes of ProFound.

        (b) There are no outstanding Contracts or waivers with respect to
ProFound extending the statutory period of limitation applicable to any Taxes
and ProFound has not requested any extension of time within which to file any
Return, which has not yet been filed.

        (c) ProFound has made provision for all Taxes payable by it and such
provision is reflected on the ProFound Financial Statements with respect to any
period covered thereby as to Taxes which are not payable prior to the date of
such Financial Statements; (ii) the provisions for Taxes with respect to
ProFound for any period prior to the Closing are adequate to cover all Taxes
with respect to such period; (iii) ProFound has withheld and paid all Taxes
required to have been withheld and paid in connection with amounts paid or owing
to any employee, independent contractor, creditor, shareholder or other Person;
(iv) all material elections with respect to Taxes made by ProFound as of the
date hereof are set forth in Section 4.8 of the ProFound Disclosure Schedule;
(v) there are no private letter rulings in respect of any Tax pending between
ProFound and any Tax Authority, if such ruling would affect ProFound; (vi)
ProFound has never been a member of an affiliated group within the meaning of
Section 1504 of the Code, or filed or been included in a combined, consolidated
or unitary return of any Person; (vii) ProFound is not liable for Taxes of any
other Person, and ProFound is not currently under any obligation to indemnify
any Person with respect to Taxes, or a party to any tax sharing agreement or any
other agreement providing for payments by ProFound with respect to Taxes; (viii)
ProFound is not, and never has been, a United States real property holding
corporation (as defined in Section 897(c)(2) of the Code), during the applicable
period

                                       17


specified in Section 897(c)(1)(A)(ii) of the Code; (ix) ProFound is not a party
to any joint venture, partnership or other arrangement or Contract which could
be treated as a partnership for Tax purposes; (x) ProFound has not agreed to or
is required, as a result of a change in method of accounting or otherwise, to
include any adjustment under Section 481 of the Code (or any corresponding
provision of Law) in taxable income; (xi) ProFound is not a party to any
Contract, arrangement or plan that could result (taking into account the
transactions contemplated by this Agreement), separately or in the aggregate, in
the payment of any "excess parachute payments" within the meaning of Section
280G of the Code (or any corresponding provision of Law); and (xii) Section 4.8
of the Disclosure Schedule contains a list of all jurisdictions to which any Tax
is properly payable or in which any Return is required to be filed by ProFound,
and no written claim has ever been made by any Tax Authority in any other
jurisdiction that ProFound is subject to taxation in such jurisdiction and
(xiii) ProFound is not jointly taxed with any other corporation under Section 31
of the Danish Act on Corporate Taxation.

        (d) ProFound has not taken any action that would jeopardize or limit its
right or ability to make use of, and has not failed to take any action that is
necessary or desirable to make full use of, the losses ProFound has incurred
since its inception against its future income under Danish tax law.

    4.9  ACCOUNTS RECEIVABLE
         -------------------

         All ProFound Accounts Receivable represent or will represent valid
obligations arising from services actually performed or sales actually made in
the ordinary course of business. All of the Accounts Receivable are or will be
collectible at the full recorded amount thereof, less any applicable reserves
established in accordance with GAAP, in the ordinary course of business and
consistent with ProFound's past practices.

    4.10 TITLE TO PROPERTIES; ENCUMBRANCES
         ---------------------------------

         Section 4.10 of the ProFound Disclosure Schedule contains a complete
and accurate list of all real property, leaseholds or other interests therein
owned or held by ProFound. ProFound does not own, and has never owned, any real
property other than as specified in Section 4.10 of the ProFound Disclosure
Schedule and, for each such property, Section 4.10 of the ProFound Disclosure
Schedule sets forth the owner thereof, a brief description thereof (including
approximate square footage), when purchased or acquired and the approximate
purchase price thereof, the use made of such property and the approximate annual
costs, fees and taxes associated with such property. ProFound has delivered or
made available to Maxygen true, correct and complete copies of the real property
leases to which ProFound is party or pursuant to which it uses or occupies any
real property. Except as set forth in Section 4.10 of the ProFound Disclosure
Schedule, ProFound has good title to all of the assets and properties, real and
personal, tangible and intangible, it owns or purports to own, or uses in its
business, including those reflected on

                                       18


its books and records and in the ProFound Financial Statements (except for
accounts receivable collected and inventories, materials and supplies disposed
of in the ordinary course of business consistent with past practice after the
date of the balance sheet included in the ProFound Interim Financial
Statements). ProFound has a valid leasehold, license or other interest in all of
the other tangible assets or properties, real or personal, which are used in the
operation of its business. Except as set forth in Section 4.10 of the ProFound
Disclosure Schedule, all assets and properties owned, leased or used by ProFound
are free and clear of all Encumbrances and Liens, except for (a) liens for
current Taxes not yet due, (b) workers', common carrier and other similar liens
arising in the ordinary course of business, none of which materially detracts
from the value or impairs the use of the asset or property subject thereto, or
impairs the operations of ProFound, (c) Encumbrances or Liens disclosed in the
ProFound Financial Statements, and (d) with respect to real property, (i) minor
imperfections of title, if any, none of which is substantial in amount,
materially detracts from the value or impairs the use of the property subject
thereto, or impairs the operations of ProFound, and (ii) zoning Laws and other
land use restrictions that do not impair the present or anticipated use of the
property subject thereto.

    4.11 CONDITION AND SUFFICIENCY OF ASSETS
         -----------------------------------

         The Facilities and other tangible assets and property owned or used by
ProFound are structurally sound, are in good operating condition and repair
(normal wear and tear excepted), and are adequate for the uses to which they are
being put, and none of such Facilities or other property and assets owned or
used by ProFound is in need of maintenance or repairs except for ordinary,
routine maintenance and repairs that are not material in nature or cost. The
Facilities and other tangible assets and property owned or used by ProFound are
sufficient for the continued conduct of its business after the Closing in
substantially the same manner as conducted prior to the Closing.

    4.12 COMPLIANCE WITH LAWS; GOVERNMENTAL AUTHORIZATIONS
         -------------------------------------------------

        (a) ProFound is in compliance in all material respects with all Laws,
licenses and Orders affecting any or all of the assets or properties owned or
used by ProFound or the business or operations of ProFound including,
Occupational Safety and Health Laws and Environmental Laws. ProFound has not
been charged with violating, or to the knowledge of ProFound, threatened with a
charge of violating, nor is ProFound under investigation with respect to a
possible violation of, any provision of any Law, Order or administrative ruling
or license relating to any of its or their assets or properties or any aspect of
its or their business.

        (b) Section 4.12 of the ProFound Disclosure Schedule contains a complete
and accurate list of each Governmental Permit that ProFound is required by Law
to hold

                                       19


or that otherwise relates to the business of, or to any of the assets or
properties owned or used by, ProFound. Each Governmental Permit listed or
required to be listed in Section 4.12 of the Disclosure Schedule is valid and in
full force and effect, has not been breached or violated by ProFound, and is not
subject to any Proceedings for suspension, modification or revocation.

    4.13 LEGAL PROCEEDINGS
         -----------------

         There is no pending Proceeding:

        (a) that has been commenced by or against ProFound or that otherwise
relates to the business of, or any of the assets or properties owned or used by,
ProFound; or

        (b) that challenges, or that may have the effect of preventing,
delaying, making illegal, or otherwise interfering with, any of the transactions
contemplated hereby.

To the knowledge of ProFound, no such Proceeding has been threatened.

    4.14 ABSENCE OF CERTAIN CHANGES AND EVENTS
         -------------------------------------

        Since December 31, 1999, ProFound has conducted its business only in the
ordinary course, consistent with past practice, and there has not been any:

         (a) declaration, setting aside, making or payment of any dividend or
other distribution or repurchase or payment in respect of any shares of capital
stock of ProFound or any warrants or other rights to acquire any shares of such
stock;

        (b) Encumbrance or Lien of or on any of its assets or properties;

        (c) except to the extent indicated in Section 4.14 of the ProFound
Disclosure Schedule, payment or increase of any bonuses, salaries or other
compensation to any shareholder, director, officer, consultant, agent or sales
representative or (except in the ordinary course of business consistent with
past practice) employee or entry into any employment, severance or similar
Contract with any director, officer or employee;

        (d) adoption of, or increase in the payments to or benefits under, any
profit sharing, bonus, deferred compensation, savings, insurance, pension,
retirement or other employee benefit plan for or with any employees, except in
the ordinary course of business consistent with past practice;

        (e) damage to or destruction of any asset or property, whether or not
covered by insurance, or loss of any customer, which could reasonably be
expected to have a ProFound Material Adverse Effect;

                                       20


        (f) entry into, termination of, or receipt of notice of termination of
any Contract or transaction involving a total remaining commitment by or to
ProFound of at least DK400,000 including the entry into (i) any document
evidencing any indebtedness; (ii) any capital or other lease; or (iii) any
guaranty;

        (g) sale, lease or other disposition (other than in the ordinary course
of business consistent with past practice) of any asset or property;

        (h) creation, incurrence or assumption of any indebtedness for borrowed
money or guarantee of any obligation or the net worth of any Person in an
aggregate amount in excess of DK400,000, except for endorsements of negotiable
instruments for collection in the ordinary course of business;

        (i) loan or advance to any Person other than travel and other similar
routine advances in the ordinary course of business consistent with past
practice, or acquisition of any capital stock or other securities of or any
ownership interest in, or a significant portion of the assets of, any other
business enterprise;

        (j) capital investment or capital expenditure or capital improvement,
addition or betterment in amounts which exceed DK400,000 in the aggregate;

        (k) institution or settlement of any Proceeding before any Governmental
Authority relating to it or its assets or properties;

        (l) change in the method of accounting or the accounting principles or
practices used by ProFound in the preparation of the ProFound Financial
Statements;

        (m) amendment or other modification of any of the Organizational
Documents of ProFound;

        (n) transfer or grant of any rights or licenses under, or entry into any
settlement regarding the infringement of, any ProFound Intellectual Property, or
entry into any licensing or similar agreements or arrangements; or

        (o) agreement, whether oral or written, by ProFound to do any of the
foregoing.

    4.15 CONTRACTS; NO DEFAULTS
         ----------------------

        (a) Section 4.15(a) of the ProFound Disclosure Schedule contains a
complete and accurate list, and ProFound has delivered to Maxygen true, correct
and complete copies, if any are in force, of:

                                       21


             (i) each Contract involving payments of at least DK400,000 that
involves performance of services or delivery of goods or materials by ProFound;

             (ii) each Contract involving payments of at least DK400,000 that
involves performance of services or delivery of goods or materials to ProFound;

             (iii) each lease and other Contract affecting any leasehold or
other interest in any real or personal property to which ProFound is a party;

             (iv) each material license agreement or other Contract to which
ProFound is a party with respect to patents, trademarks, copyrights, biologic or
other materials, trade secrets or other Intellectual Property, including
agreements with current or former employees, consultants or contractors
regarding the use or disclosure of any intellectual property;

             (v) each collective bargaining agreement and other Contract to or
with any labor union or other employee representative of a group of employees
involving or affecting ProFound;

             (vi) each joint venture, partnership and other Contract involving a
sharing of profits, losses, costs or liabilities by ProFound with any other
Person or requiring ProFound to make a capital contribution;

             (vii) each Contract to which ProFound is a party containing
covenants that in any way purport to restrict the business activity of ProFound
or any of the ProFound Securityholders or limit the freedom of ProFound or any
of the ProFound Securityholders to engage in any line of business or to compete
with any Person or hire any Person;

             (viii) each employment or consulting agreement between ProFound and
its employees and consultants;

             (ix) each agreement between ProFound and an officer or director of
ProFound or any affiliate of any of the foregoing;

             (x) each Contract for capital expenditures by ProFound in excess of
DK400,000;

             (xi) each agreement of ProFound under which any money has been or
may be borrowed or loaned or any note, bond, factoring agreement, indenture or
other evidence of indebtedness has been issued or assumed (other than those
under which there remain no ongoing obligations of ProFound), and each guaranty
by ProFound of any evidence of indebtedness or other obligation, or of the net
worth, of any Person (other than endorsements for the purpose of collection in
the ordinary course of business);

                                       22


             (xii) each stock purchase, merger or other agreement pursuant to
which ProFound acquired any material amount of assets (other than capital
expenditures), and all relevant documents and agreements delivered in connection
therewith;

             (xiii) each agreement pursuant to which ProFound has issued any
equity securities;

             (xiv) each agreement to which ProFound is a party containing a
change of control provision; and

             (xv) each other agreement to which ProFound is a party having an
indefinite term or a fixed term of more than one year (other than those that are
terminable at will or upon not more than 30 days' notice by ProFound without
penalty) or requiring payments by ProFound of more than DK400,000 per year.

        (b) Each Contract identified or required to be identified in Section
4.15(a) of the ProFound Disclosure Schedule is in full force and effect and is
valid and enforceable against ProFound and, to the knowledge of ProFound,
against the other parties thereto in accordance with its terms.

        (c) ProFound is in full compliance with all applicable terms and
requirements of each Contract under which ProFound has any obligation or
liability or by which ProFound or any of the assets or properties owned or used
by ProFound is or was bound, except for such noncompliance that could not
reasonably be expected to have a ProFound Material Adverse Effect.

        (d) To the knowledge of ProFound, each other Person that has or had any
obligation or liability under any Contract under which ProFound has any rights
is in full compliance with all applicable terms and requirements of such
Contract.

        (e) To the knowledge of ProFound, no event has occurred and no
circumstance exists that (with or without notice or lapse of time or both) is
likely to result in a material violation or breach of any Contract.

    4.16 INSURANCE
         ---------

         Section 4.16 of the ProFound Disclosure Schedule sets forth the premium
payments and describes all the insurance policies of ProFound. These policies
are now in full force and effect in accordance with their terms and expire on
the dates shown on Section 4.16 of the ProFound Disclosure Schedule. There has
been no default in the payment of premiums on any of such policies, and there is
no ground for cancellation or avoidance of any such policies, or any increase in
the premiums thereof, or for reduction of the coverage provided thereby. Such
policies shall continue in full force and effect up to the expiration dates
shown in Section 4.16 of the Disclosure Schedule. True, correct

                                       23


and complete copies of all insurance policies listed in Section 4.16 of the
ProFound Disclosure Schedule have been previously furnished to Maxygen.

    4.17 ENVIRONMENTAL MATTERS
         ---------------------

        (a) ProFound is in compliance with all applicable Environmental Laws
including, but is not limited to, the possession by ProFound of all Governmental
Permits required under applicable Environmental Laws, and compliance with the
terms and conditions thereof. ProFound has not received notice of, and neither
ProFound nor any predecessor is the subject of, any Environmental Claim or
Remedial Action. There are no circumstances or conditions related to ProFound,
ProFound's operations or any Facility that are reasonably likely to prevent or
interfere with such compliance or give rise to an Environmental Claim or
Remedial Action in the future.

        (b) There are no Environmental Claims that are pending or, to the
knowledge of ProFound, threatened against ProFound, any Facility or against any
Person whose liability for any Environmental Claim ProFound has retained or
assumed either contractually or by operation of Law.

        (c) Neither ProFound, nor any other Person acting on behalf of ProFound
(solely with respect to any such other Person, with ProFound's knowledge) has
(A) disposed of, transported or arranged for the disposal of any Hazardous
Materials to, at or upon: (i) any location other than a site lawfully permitted
to receive such Hazardous Materials or (ii) any Facilities and (B) there has not
occurred during the period ProFound operated or possessed any Facility or is
presently occurring a Release, or threatened Release, of any Hazardous Materials
on, into or beneath the surface of, or adjacent to, any Facilities.

         (d) Section 4.17 of the ProFound Disclosure Schedule identifies (i) all
environmental audits, assessments, or occupational health studies undertaken by
ProFound or its agents on its behalf, or undertaken by any Governmental
Authority, or any Person, relating to the Facilities; (ii) the results of any
groundwater, soil, air or asbestos monitoring undertaken by ProFound or its
agents on its behalf, or, to the knowledge of ProFound, undertaken by any
Governmental Authority or any third Person, relating to any Facility; and (iii)
all written communications between ProFound and any Governmental Authority
arising under or related to Environmental Laws.

    4.18 EMPLOYEES
         ---------

        (a) Section 4.18 of the ProFound Disclosure Schedule contains a complete
and accurate list of the following information for each employee of ProFound:
name; job title; base salary; bonus; vacation accrued; service credited for
purposes of vesting and

                                       24


eligibility to participate under any employee benefit plan of any nature; and
whether such employee is a party to a non-competition agreement with ProFound.

        (b) No Founding Shareholder and, to the knowledge of ProFound, no
employee of ProFound, is a party to, or is otherwise bound by, any agreement or
arrangement, including any non-competition or similar agreement, between such
Founding Shareholder or employee and any other Person that could materially
adversely affect (i) the performance of his or her duties as an officer or
employee of, or consultant to, ProFound, or (ii) the ability of ProFound to
conduct its business as previously conducted or presently proposed to be
conducted in the future. Since December 31, 1999, no officer or other employee
has terminated and, to the knowledge of ProFound, no other officer or employee
of ProFound intends to terminate, his or her employment or consulting
relationship with ProFound.

        (c) No employee of ProFound is bound by any agreement with any other
Person that is violated or breached by such employee performing the services he
or she is performing for ProFound in connection with the business presently
conducted or presently proposed to be conducted by ProFound in the future.

        (d) ProFound has delivered to Maxygen prior to the date hereof true and
complete copies of any employment agreements and any procedures and policies
relating to the employment of employees of ProFound and the use of temporary
employees and independent contractors by ProFound (including summaries of any
procedures and policies that are unwritten).

    4.19 EMPLOYEE BENEFITS
         -----------------

        (a) ProFound does not maintain, have an obligation to contribute to or
have any actual or contingent liability with respect to any Employee Benefit
Plan. ProFound has delivered to Maxygen prior to the date hereof true and
complete copies of (i) plan instruments and amendments thereto for all Employee
Benefit Plans (or written summaries of any Employee Benefit Plans that are
unwritten) and related trust agreements, insurance and other contracts, summary
plan descriptions, and summaries of material modifications, and material
communications distributed to the participants of each Plan, (ii) to the extent
annual reports are required with respect to any Employee Benefit Plan, the three
most recent annual reports and attached schedules for each Employee Benefit Plan
as to which such report is required to be filed and (iii) where applicable, the
most recent (A) opinion, notification and determination letters, (B) audited
financial statements, and (C) actuarial valuation reports.

        (b) Each Employee Benefit Plan which provides health, disability or
death benefits is fully insured; ProFound is not obligated to directly pay any
such benefits or to reimburse any third Person payor for the payment of such
benefits.

                                       25


        (c) Each Employee Benefit Plan is and has been operated in material
compliance with its terms and all applicable Laws, Orders or governmental rules
and regulations currently in effect with respect thereto, and by its terms can
be amended and/or terminated at any time. As of and including the Closing,
ProFound (i) shall have performed all material obligations required to be
performed by it under, and shall not be in material default under or in material
violation of any Employee Benefit Plan and (ii) shall have made all
contributions or payments required to be made by it up to and including the
Closing with respect to each Employee Benefit Plan, or adequate accruals
therefor will have been provided for and will be reflected on the ProFound
Financial Statements. All notices, filings and disclosures required by any Law
have been timely made.

        (d) ProFound has not received notice of and is not aware of any
Proceeding (other than routine claims for benefits) pending or, to the knowledge
of ProFound, threatened with respect to any Employee Benefit Plan or against any
fiduciary of any Employee Benefit Plan, and there are no facts that could give
rise to any such Proceeding. There has not occurred any circumstances by reason
of which ProFound may be liable for an act, or a failure to act, by a fiduciary
with respect to any Employee Benefit Plan.

        (e) There are no Proceedings against ProFound pending or, to ProFound's
knowledge, threatened and no facts exist as a result of which ProFound could
have any liability based on, arising out of, in connection with or otherwise
relating to the classification of any individual by ProFound as an independent
contractor.

        (f) Section 4.19(f) of the ProFound Disclosure Schedule sets forth a
true and complete list of each current or former employee, officer or director
of ProFound who holds (i) any warrant or option to purchase ProFound Common
Stock, together with the number of shares of ProFound Common Stock subject to
such warrant or option, the exercise price of such warrant or option (to the
extent determinable), and the expiration date of such warrant or option; (ii)
any shares of ProFound Common Stock that are restricted as a result of an
agreement with ProFound or the stock plan of ProFound; and (iii) any other
right, directly or indirectly, to receive ProFound securities or any other
compensation based in whole or in part on the value of ProFound capital stock,
together with the number of shares of ProFound stock subject to such right.

        (g) Section 4.19(g) of the ProFound Disclosure Schedule sets forth a
true and complete list of (i) all agreements with consultants who are
individuals obligating ProFound to make annual cash payments in an amount
exceeding DK200,000; and (ii) all agreements with respect to the services of
independent contractors or leased employees who are individuals or individuals
doing business in a corporate form whether or not they participate in any of the
Employee Benefit Plans.

                                       26


        (h) No Employee Benefit Plan invests in ProFound Securities; and (ii)
the consummation of the transactions contemplated by this Agreement will not,
alone or together with any other event, (A) entitle any employee or former
employee of ProFound to any payment, (B) result in an increase in the amount of
compensation or benefits or accelerate the vesting or timing of payment of any
benefits or compensation payable in respect of any employee or former employee
or (C) result in any parachute payment, whether under the Danish Salaried
Employees Act, any other Danish law or any private agreement, and whether or not
such payment is considered reasonable compensation for services rendered.
ProFound will take all actions within its control to ensure that all actions
required to be taken by a fiduciary of any Employee Benefit Plan in order to
effectuate the transaction contemplated by this Agreement shall comply with the
terms of such Plan and applicable Law.

        (i) No Employee Benefit Plan provides benefits, including, without
limitation, death or medical benefits (through insurance or otherwise) with
respect to any employee or former employee of ProFound beyond their retirement
or other termination of service other than (i) coverage mandated by applicable
Law, (ii) retirement or death benefits under any Pension Plan, (iii) disability
benefits under any welfare plan that have been fully provided for by insurance
or otherwise, (iv) deferred compensation benefits accrued as liabilities on the
ProFound Financial Statements or (v) benefits in the nature of severance pay.

        (j) ProFound has not proposed, agreed to or announced any changes to any
Employee Benefit Plan that would cause an increase in benefits under any such
Employee Benefit Plan (or the creation of new benefits or plans) or to change
any employee coverage which would cause an increase in the expense of
maintaining any such plan.

        (k) No Employee Benefit Plan provides for the payment of severance
benefits.

        (l) Section 4.19(l) of the ProFound Disclosure Schedule summarizes all
amounts that would be required by any applicable law to be paid to the employees
of ProFound who terminate employment or are terminated.

    4.20 LABOR RELATIONS
         ---------------

        (a) Since December 31, 1999, no employee of ProFound has terminated, and
to the knowledge of ProFound, no ProFound employee is considering terminating,
his or her employment with ProFound.

        (b) To the knowledge of ProFound, no condition or state of facts or
circumstances exists which could materially adversely affect ProFound's
relations with its

                                       27


employees, including the consummation of the transactions contemplated by this
Agreement.

        (c) ProFound is in compliance in all material respects with all
applicable Law respecting employment and employment practices, terms and
conditions of employment and wages and hours and none of them is engaged in any
unfair labor practice.

        (d) No collective bargaining agreement with respect to the business of
ProFound is currently in effect or being negotiated. ProFound has not
encountered any labor union or collective bargaining organizing activity with
respect to its employees. ProFound has no obligation to negotiate any such
collective bargaining agreement, and, to the knowledge of ProFound, there is no
indication that the employees of ProFound desire to be covered by a collective
bargaining agreement.

        (e) There are no strikes, slowdowns, work stoppages or other labor
trouble pending or, to the knowledge of ProFound, threatened with respect to the
employees of ProFound, nor has any of the above occurred or, to the knowledge of
ProFound, been threatened.

        (f) There is no representation claim or petition pending before the
National Labor Relations Board or any state or local labor agency and, to the
knowledge of ProFound, no question concerning representation has been raised or
threatened respecting the employees of ProFound.

        (g) There are no complaints or charges against ProFound pending before
the ordinary courts, the Danish Industrial Tribunal, industrial arbitration
tribunal, the Danish Working Environment Service or other Danish Governmental
Authority, and, to the knowledge of ProFound, no complaints or charges have been
filed or threatened to be filed against ProFound with any such board or agency.

        (h) To the knowledge of ProFound, no charges with respect to or relating
to the business of ProFound are pending before any agency responsible for the
prevention of unlawful employment practices.

        (i) Section 4.20(i) of the ProFound Disclosure Schedule accurately sets
forth all unpaid severance which, as of the date hereof, is due or claimed, in
writing, to be due from ProFound to any Person whose employment with ProFound
was terminated.

        (j) ProFound has not received notice of the intent of any Governmental
Authority responsible for the enforcement of labor or employment Laws to conduct
an investigation of ProFound, and no such investigation is in progress.

                                       28


        (k) ProFound is not and, to the knowledge of ProFound, no employee of
ProFound is, in violation in any material respect of any employment agreement,
non-disclosure agreement, non-compete agreement or any other agreement regarding
an employee's employment with ProFound.

        (l) ProFound has paid all wages which are due and payable to

each of its employees and each of its independent contractors.

    4.21 INTELLECTUAL PROPERTY
         ---------------------

        (a) For the purposes of this Agreement, the following terms have the
following definitions:

         "Intellectual Property" shall mean any or all of the following and all
          ---------------------
rights in, arising out of, or associated therewith: (i) all United States,
international and foreign patents and applications therefor and all reissues,
divisions, renewals, extensions, provisionals, continuations and
continuations-in-part thereof; (ii) all inventions (whether patentable or not),
invention disclosures, improvements, trade secrets, proprietary information,
know how, technology, technical data and customer lists, and all documentation
relating to any of the foregoing; (iii) all copyrights, copyrights registrations
and applications therefor, and all other rights corresponding thereto throughout
the world; (iv) all industrial designs and any registrations and applications
therefor throughout the world, (v) all trade names, logos, URLs, common law
trademarks and service marks, trademark and service mark registrations and
applications therefor throughout the world; (vi) all databases and data
collections and all rights therein throughout the world; (vii) all moral and
economic rights of authors and inventors, however denominated, throughout the
world, and (viii) any similar or equivalent rights to any of the foregoing
anywhere in the world.

         "ProFound Intellectual Property" shall mean any Intellectual Property
          ------------------------------
that is owned by, or exclusively licensed to ProFound.

         "Registered Intellectual Property" means all United States,
          --------------------------------
international and foreign: (i) patents and patent applications (including
provisional applications); (ii) registered trademarks, applications to register
trademarks, intent-to-use applications, or other registrations or applications
related to trademarks; (iii) registered copyrights and applications for
copyright registration; and (iv) any other Intellectual Property that is the
subject of an application, certificate, filing, registration or other document
issued, filed with, or recorded by any state, government or other public legal
authority.

         "ProFound Registered Intellectual Property" means all of the Registered
          -----------------------------------------
Intellectual Property owned by, or filed in the name of, ProFound.

                                       29


        (b) No material ProFound Intellectual Property or product or service of
ProFound is subject to any Proceeding or outstanding Order, agreement, or
stipulation restricting in any manner the use, transfer, or licensing thereof by
ProFound, or which may affect the validity, use or enforceability of such
ProFound Intellectual Property.

        (c) Section 4.21 of the ProFound Disclosure Schedule is a complete and
accurate list of all ProFound Registered Intellectual Property and specifies,
where applicable, the jurisdictions in which each such item of ProFound
Registered Intellectual Property has been issued or registered or in which an
application for such issuance and registration have been filed, including the
respective registration or application numbers. Each material item of ProFound
Registered Intellectual Property is valid and subsisting, all necessary
registration, maintenance and renewal fees currently due in connection with such
ProFound Registered Intellectual Property have been made and all necessary
documents, recordations and certificates in connection with such ProFound
Registered Intellectual Property have been filed with the relevant patent,
copyright, trademark or other authorities in the United States or foreign
jurisdictions, as the case may be, for the purposes of maintaining such ProFound
Registered Intellectual Property.

        (d) ProFound owns and has good and exclusive title to, or has license
(sufficient for the conduct of its business as currently conducted and as
proposed to be conducted) to, each material item of ProFound Intellectual
Property or other Intellectual Property used by ProFound free and clear of any
Lien or Encumbrance (excluding licenses and related restrictions); and ProFound
is the exclusive owner of all trademarks and trade names used in connection with
the operation or conduct of the business of ProFound, including the sale of any
products or the provision of any services by ProFound.

        (e) ProFound owns exclusively, and has good title to, all copyrighted
works that are products of ProFound or which ProFound otherwise expressly
purports to own.

        (f) To the extent that any material Intellectual Property has been
developed or created by any Person for ProFound, ProFound has a written
agreement with such Person with respect thereto and ProFound thereby either (i)
has obtained ownership of, and is the exclusive owner of, or (ii) has obtained a
license (sufficient for the conduct of its business as currently conducted and
as proposed to be conducted) to all such Person's Intellectual Property in such
work, material or invention by operation of law or by valid assignment, to the
fullest extent it is legally possible to do so.

        (g) ProFound has not transferred ownership of, or granted any exclusive
license with respect to, any Intellectual Property that is or was material to
ProFound's Intellectual Property, to any third party.

                                       30


        (h) The ProFound Disclosure Schedule lists all material contracts,
licenses and agreements to which ProFound is a party (i) with respect to
ProFound Intellectual Property licensed or transferred to any third party (other
than end-user licenses in the ordinary course); or (ii) pursuant to which a
third party has licensed or transferred any material Intellectual Property to
ProFound.

        (i) All material contracts, licenses and agreements relating to ProFound
Intellectual Property are in full force and effect. The consummation of the
transactions contemplated by this Agreement will neither violate nor result in
the breach, modification, cancellation, termination, or suspension of such
contracts, licenses and agreements. ProFound is in material compliance with, and
has not materially breached any term of such contracts, licenses and agreements
and, to the knowledge of ProFound, all other parties to such contracts, licenses
and agreements are in compliance with, and have not materially breached any term
of, such contracts, licenses and agreements. Following the Closing, ProFound
will be permitted to exercise all ProFound rights under such contracts, licenses
and agreements to the same extent ProFound would have been able to had the
transactions contemplated by this Agreement not occurred and without the payment
of any additional amounts or consideration other than ongoing fees, royalties or
payments which ProFound would otherwise be required to pay.

        (j) In operating its business since the inception of ProFound (including
its design, development, manufacture, marketing and sales of products and
services), ProFound has not infringed or misappropriated any Intellectual
Property of any third Person or engaged in unfair competition or any unlawful
trade practice.

        (k) ProFound has not received notice from any third party that the
operation of the business of ProFound or any act, product or service of
ProFound, infringes or misappropriates the Intellectual Property of any third
party or constitutes unfair competition or trade practices under the laws of any
jurisdiction.

        (l) Except as set forth in Section 4.21 of the ProFound Disclosure
Schedule and to the knowledge of ProFound, no Person has infringed or
misappropriated or is infringing or misappropriating any ProFound Intellectual
Property.

        (m) ProFound has taken reasonable steps to protect the rights of
ProFound in ProFound's confidential information and trade secrets that it wishes
to protect or any trade secrets or confidential information of third parties
provided to ProFound, and, without limiting the foregoing, ProFound has and
enforces, or prior to the Closing will have and will enforce, a policy requiring
each employee and contractor to execute a proprietary
information/confidentiality agreement substantially in the form provided to
Maxygen and all current and former employees and contractors of ProFound have
executed such an agreement, except where the failure to do so is not reasonably
expected to be material to ProFound.

                                       31


        (n) Neither this Agreement nor the transactions contemplated by this
Agreement will result in (i) ProFound granting to any third party any right to
or with respect to any material Intellectual Property right owned by, or
licensed to, either of them, (ii) ProFound being bound by, or subject to, or any
non-compete or other material restriction on the operation or scope or their
respective businesses, or (iii) ProFound being obligated to pay any royalties or
other material amounts to any third party in excess of those payable by
ProFound, in the absence of this Agreement or the transaction contemplated
hereby.

    4.22 CERTAIN PAYMENTS
         ----------------

         Neither ProFound nor any shareholder, director, officer, agent or
employee of ProFound, or to the knowledge of ProFound, any other Person
associated with or acting for or on behalf of ProFound, has directly or
indirectly (a) made any contribution, gift, bribe, rebate, payoff, influence
payment, kickback or other payment to any Person, private or public, regardless
of form, whether in money, property or services: (i) to obtain favorable
treatment in securing business, (ii) to pay for favorable treatment for business
secured, or (iii) to obtain special concessions, or for special concessions
already obtained, for or in respect of ProFound or any affiliate of ProFound, or
(b) established or maintained any fund or asset of ProFound that has not been
recorded in the consolidated books and records of ProFound.

    4.23 RELATIONSHIPS WITH RELATED PERSONS
         ----------------------------------

         No stockholder, affiliate, officer, director or employee of ProFound,
nor any spouse or child of any of them or any Person associated with any of them
("Related Person"), has any ownership interest in any assets or properties
(including, without limitation, any Intellectual Property) used in or pertaining
to the business of ProFound. No stockholder, affiliate, officer or director, or
spouse or child of any of them, owns or owned, directly or indirectly, and
whether on an individual, joint or other basis, any equity interest or any other
financial or profit interest in any Person (other than less than two percent
(2%) of the outstanding capital stock of a Person) that (i) has or had business
dealings involving a total value in excess of DK100,000 with ProFound since the
inception of ProFound, or (ii) engaged in competition with ProFound. Except as
set forth in Section 4.23 of the ProFound Disclosure Schedule, no stockholder,
affiliate, officer, director or employee of ProFound nor any Related Person is a
party to any Contract with, or has any claim or right against, or owes any
amounts to, ProFound. All loans, payables and other amounts due to or from
ProFound and its affiliates are listed in Section 4.23 of the ProFound
Disclosure Schedule. As used in this Section 4.23, "stockholder" does not
include BankInvest I, BankInvest II, Novo Nordisk A/S or any corporate affiliate
of any of them.

                                       32


    4.24 BROKERS OR FINDERS
         ------------------

         Neither ProFound nor any of its agents has incurred any obligation or
liability, contingent or otherwise, for brokerage or finders' fees or agents'
commissions or financial advisory services or other similar payment in
connection with this Agreement or the Transaction Documents or the transactions
contemplated hereby or thereby.

    4.25 CUSTOMER RELATIONSHIPS
         ----------------------

         To the knowledge of ProFound, there are no facts or circumstances,
including the consummation of the transactions contemplated by this Agreement,
that are reasonably likely to result in the loss of any material Customer of
ProFound or a material change in the relationship of ProFound with such a
Customer.

    4.26 RESTRICTIONS ON BUSINESS ACTIVITIES
         -----------------------------------

         There is no Contract or Order binding upon ProFound or, to the
knowledge of ProFound, threatened that has, or could reasonably be expected to
have, the effect of prohibiting or materially impairing any business practice of
ProFound (either individually or in the aggregate), any acquisition of property
by ProFound (either individually or in the aggregate), providing of any service
by ProFound or the hiring of employees or the conduct of business by ProFound
(either individually or in the aggregate).

    4.27 OUTSTANDING INDEBTEDNESS
         ------------------------

         Section 4.27 of the ProFound Disclosure Schedule sets forth as
of the date of the balance sheet included in the ProFound Interim Financial
Statements (a) the amount of all indebtedness for borrowed money of ProFound
then outstanding, the interest rate and maturity of that indebtedness, and the
amount of any prepayment penalty or premium applicable to that indebtedness, (b)
any Encumbrances or Liens which relate to such indebtedness and (c) the name of
the lender or the other payee of each such indebtedness.

    4.28 DEPOSIT ACCOUNTS
         ----------------

         Section 4.28 of the ProFound Disclosure Schedule contains a true,
correct and complete list of (a) the name of each financial institution in which
ProFound has an account or safe deposit box, (b) the names in which each account
or box is held, (c) the type of account, and (d) the name of each Person
authorized to draw on or have access to each account or box.

                                       33


    4.29 DISCLOSURE
         ----------

         No representation or warranty of ProFound or any ProFound Shareholder
in this Agreement as modified by statements in the ProFound Disclosure Schedule
is inaccurate in any material respect or omits to state a material fact
necessary to make the statements herein or therein, in light of the
circumstances under which they were made, not misleading.

5.       REPRESENTATIONS AND WARRANTIES OF THE PROFOUND SHAREHOLDERS
         -----------------------------------------------------------

         Each ProFound Shareholder hereby represents and warrants to Maxygen and
Holdings as follows:

    5.1 AUTHORITY
        ---------

         Each ProFound Shareholder has the right, power, authority and capacity
to execute and deliver this Agreement and the Transaction Documents to which it
is or will become a party, to consummate the Maxygen Exchange and the other
transactions contemplated hereby and thereby and to perform its respective
obligations under this Agreement and the Transaction Documents to which it is or
will become a party. This Agreement has been duly authorized, executed and
delivered by it and is enforceable against it in accordance with the terms
hereof. It has all authorizations and consents necessary for the execution and
delivery of this Agreement, and for the performance of its obligations
hereunder. If such ProFound Shareholder is not a natural Person, it is and at
the Closing will be duly organized, validly existing and in good standing under
the laws of the jurisdiction of its organization with corporate power and
authority to own, lease and operate its properties and to conduct its business.
Upon the authorization and approval, execution and delivery by or on behalf of
the respective ProFound Shareholder of the Transaction Documents to which it is
or will become a party, such Transaction Documents will constitute legal, valid
and binding obligations of the respective ProFound Shareholder, enforceable
against such holder in accordance with their respective terms.

    5.2 OWNERSHIP
        ---------

         It has, and at the Closing will have, (i) good and marketable title to
all the ProFound Securities listed beside its name in Section 4.3 of the
ProFound Disclosure Schedule (as to the applicable ProFound Shareholder, the
"Applicable Securities"), free and clear of all Encumbrances and Liens, and (ii)
full legal right and power to sell, transfer and deliver the Applicable
Securities to Maxygen in accordance with this Agreement. The Applicable
Securities are the only securities of ProFound held by the ProFound Shareholder.
Upon delivery of the Applicable Securities to be exchanged by it

                                       34


to Maxygen in accordance with this Agreement, Maxygen will receive good and
marketable title to all the Applicable Securities, free and clear of all
Encumbrances and Liens.

    5.3  TAXES
         -----

          On the Closing all stock transfer or other taxes (other than income
taxes) that are required to be paid in connection with the exchange and transfer
of the ProFound Securities to Maxygen will have been fully paid or provided for
and all laws imposing such taxes will have been fully complied with.

    5.4  NO CONFLICT
         -----------

          None of the execution, delivery or performance of this Agreement or
any of the Transaction Documents to which such ProFound Shareholder is or will
become a party, and the consummation of the transactions contemplated herein or
therein by it conflicts or will conflict with or results or will result in any
breach or violation of any of the terms or provisions of, or constitute a
default under, or result in the creation or imposition of any lien or
encumbrance upon, any of its properties or assets pursuant to (i) the terms of
its Organizational Documents; (ii) the terms of any contract or other agreement
to which it is a party or by which it is bound or to which any of its properties
is subject, which conflict, breach, violation or default would adversely affect
the ProFound Shareholder's ability to perform its obligations hereunder or
thereunder; (iii) any statute, rule or regulation of any Governmental Authority
having jurisdiction over it or any of its activities or properties; or (iv) the
terms of any Order of any arbitrator or any Governmental Authority having such
jurisdiction.

    5.5  NO CONSENT
         ----------

          No consent, approval, authorization or order of, or any filing or
declaration with any Governmental Authority is required for the consummation by
the ProFound Shareholder of any of the transactions on its part contemplated
under this Agreement.

    5.6  INVESTMENT
         ----------

          Such ProFound Shareholder is acquiring the Maxygen securities for
investment, for its own account and not with a view to distribution, it being
understood that some of the ProFound Shareholders may sell some of their shares
of Maxygen Common Stock to Maxygen.  Such ProFound Shareholder acknowledges that
the Maxygen Common Stock will not be registered under the Securities Act and
will be subject to restrictions on transfer under the United States securities
laws and the terms of the applicable Lock-up Agreement.

                                       35


    5.7  BROKERS AND FINDERS
         --------------------

          The ProFound Shareholder has not retained any investment banker,
broker, or finder in connection with any of the transactions contemplated by
this Agreement.

    5.8  UNREGISTERED SECURITIES
         -----------------------

          The ProFound Shareholder understands and acknowledges that the
offering of the Maxygen securities pursuant to this Agreement will not be
registered under the Securities Act on the grounds that the offering and sale of
Maxygen securities contemplated by this Agreement are exempt from registration
pursuant to Section 4(2) and/or Section 3(b) of the Securities Act and
Regulations S and D thereunder and that Maxygen's reliance upon such exemption
is predicated upon such ProFound Shareholder's representations as set forth in
this Agreement.

    5.9  EXPERIENCE
         ----------

          Each ProFound Shareholder represents that:  (a) it has such knowledge
and experience in financial and business matters as to be capable of evaluating
the merits and risks of its prospective investment in the Maxygen securities;
(b) it believes it has received all the information it has requested from
Maxygen and considers necessary or appropriate for deciding whether to obtain
Maxygen securities; (c) it has had the opportunity to discuss Maxygen's
business, management, and financial affairs with Maxygen management, it being
understood that, in the case of Novo Nordisk A/S, that opportunity has arisen
primarily in the context of Novo Nordisk A/S's separate business relationship
with Maxygen.

    5.10  NON-U.S. PERSON STATUS
          ----------------------

          The ProFound Shareholder, if a natural person, is not a resident of
the United States.  The ProFound Shareholder, if a partnership or corporation:
(a) is organized or incorporated in a jurisdiction other than a jurisdiction
that is part of the United States and (b) was not formed by a "U.S. person"
principally for the purpose of investing in securities that are not registered
under the Securities Act.  Each ProFound Shareholder is a natural person, a
partnership or a corporation.  For purposes of this Section 5.10, "U.S. person"
has the meaning given to that term in Regulation S adopted by the Commission
under the Securities Act.

6.  REPRESENTATIONS AND WARRANTIES OF MAXYGEN
    -----------------------------------------

          Except as set forth in the Maxygen Disclosure Schedule by means of a
disclosure that references the specific representation and warranty which that
exception is intended to modify, or in the Maxygen Reports filed with the
Commission on or prior to

                                       36


the date hereof, Maxygen hereby represents and warrants to ProFound and the
ProFound Shareholders as follows:

    6.1  ORGANIZATION AND GOOD STANDING
         ------------------------------

        (a)  Section 6.1 of the Maxygen Disclosure Schedule contains a complete
and accurate list of the jurisdictions in which Maxygen is authorized to do
business. Maxygen is a corporation duly organized, validly existing and in good
standing under the laws of Delaware. Holdings is a corporation duly organized,
validly existing and in good standing under the laws of the Cayman Islands. Each
of Maxygen and Holdings has full corporate power and authority to conduct its
business as it is now being conducted and to own or use the assets and
properties that it purports to own or use. Each of Maxygen and Holdings is duly
qualified to do business as a foreign corporation and is in good standing under
the Laws of each state or other jurisdiction in which either the ownership or
use of the assets or properties owned or used by it, or the nature of the
activities conducted by it, requires such qualification, except where the
failure to be so qualified could not reasonably be expected to have a Maxygen
Material Adverse Effect.

        (b)  Within 15 days after the date of this Agreement, Maxygen will
deliver to ProFound correct and complete copies of the Organizational Documents
of Maxygen and Holdings.

    6.2  AUTHORITY; NO CONFLICT
         ----------------------

        (a)  Maxygen and Holdings have the right, power, authority and capacity
to execute and deliver this Agreement and the Transaction Documents to which
they are or will become a party, to consummate the Exchanges and the other
transactions contemplated hereby and thereby and to perform their respective
obligations under this Agreement and the Transaction Documents to which they are
or will become a party. This Agreement has been duly authorized and approved,
executed and delivered by Maxygen and Holdings and constitutes the legal, valid
and binding obligation of Maxygen and Holdings, enforceable against Maxygen and
Holdings in accordance with its terms. Upon the authorization and approval,
execution and delivery by Maxygen and Holdings of the Transaction Documents to
which they are or will become a party, such Transaction Documents will
constitute legal, valid and binding obligations of Maxygen and Holdings,
enforceable against Maxygen and Holdings in accordance with their respective
terms.

        (b)  Neither the execution and delivery of this Agreement or any
Transaction Document by Maxygen or Holdings nor the consummation or performance
by Maxygen or Holdings of the Exchanges or any of the other transactions
contemplated hereby or thereby will, directly or indirectly (with or without
notice or lapse of time or both):

                                       37


             (i)   contravene, conflict with or result in a violation or breach
of (A) any provision of the Organizational Documents of Maxygen or Holdings, (B)
any resolution adopted by the board of directors or the stockholders of Maxygen
or Holdings, (C) any legal requirement or any Order, award, decision, settlement
or process to which Maxygen or Holdings or any of the assets or properties owned
or used by Maxygen or Holdings may be subject, or (D) any Governmental Permit
that is held by Maxygen or Holdings;

             (ii)  result in a breach of or constitute a default, give rise to a
right of termination, cancellation or acceleration, create any entitlement to
any payment or benefit, or require the consent, authorization or approval of or
any notice to or filing with any third Person under any material Contract to
which Maxygen or Holdings is a party or to which their respective assets or
properties are bound, or require the consent, authorization or approval of or
any notice to or filing with any Governmental Authority to which Maxygen or
Holdings or their respective assets or properties is subject; or

             (iii) result in the imposition or creation of any Encumbrance or
Lien upon or with respect to any of the assets or properties owned or used by
Maxygen or Holdings.

    6.3  MAXYGEN REPORTS
         ---------------

        (a)  Maxygen has made available to each ProFound Shareholder Maxygen's
final prospectus dated March 20, 2000 and will make available to each ProFound
Shareholder its Annual Report on Form 10-K for the year ended December 31, 1999
and any and all reports required to be filed by Maxygen after the date of this
Agreement and before the Closing with the Commission pursuant to the Exchange
Act (collectively, the "Maxygen Reports").

        (b)  The Maxygen Reports complied and will comply as to form in all
material respects with the requirements of the Securities Act and the Exchange
Act in effect on the dates thereof. The Maxygen Reports, when filed pursuant to
the Securities Act and the Exchange Act, did not and will not contain any untrue
statement of a material fact or omit to state any material fact necessary in
order to make the statements therein, in light of the circumstances under which
they were made, not misleading.

        (c)  Each of the Maxygen financial statements (including the related
notes) included in the Maxygen Reports present fairly or will present fairly, in
all material respects, the consolidated financial position and consolidated
results of operations, changes in shareholders' equity and cash flow of Maxygen
as of the respective dates or for the respective periods set forth therein, all
in conformity with United States generally accepted accounting principles
consistently applied during the periods involved except as otherwise noted
therein, and subject, in the case of any unaudited interim financial

                                       38


statements included therein, to normal year-end adjustments and to absence of
complete footnotes.

    6.4  ABSENCE OF CERTAIN CHANGES AND EVENTS
         -------------------------------------

          Since December 31, 1999, Maxygen has conducted its business only in
the ordinary course and there has not been (i) any Maxygen Material Adverse
Effect; (ii) any declaration, setting aside or payment of any dividend or other
distribution with respect to its capital stock; or (iii) any material change in
its accounting principles, practices or methods.

    6.5  VALIDITY OF SECURITIES
         ----------------------

          The Maxygen Common Stock, when issued, sold, and delivered in
accordance with the terms and for the consideration expressed in this Agreement,
will be duly and validly issued (including, without limitation, issued in
compliance with applicable federal and state securities laws) and non-
assessable.  The Maxygen Common Stock issuable upon exercise of the Maxygen
Options will have been duly and validly reserved and, assuming such Maxygen
Common Stock is issued to the ProFound Securityholders in accordance with the
Maxygen International Option Plan, will be duly and validly issued (including,
without limitation, issued in compliance with applicable United States and state
securities laws) and non-assessable.

    6.6  HOLDINGS
         --------

          Holdings has been formed for the purpose of holding the securities of
entities that conduct some or all of the future non-U.S. operations of the
Maxygen entities, including ProFound, and holding certain intangible and other
assets.

    6.7  SHORT SWING PROFIT RULE
         -----------------------

          Maxygen believes that, for so long as the Founding Shareholders'
duties and responsibilities at ProFound are no greater than those contemplated
by the Employment Agreements (see Section 7.9) and assuming no relevant change
in the interpretation of the Exchange Act by courts or the Commission, none of
the Founding Shareholders will be a person covered by Section 16(a) of the
Exchange Act and thus will not be subject to the short swing profits rule of
Section 16(b) of the Exchange Act.

                                       39


7.  COVENANTS
    ---------

    The parties, as applicable, hereby covenant and agree as follows:

    7.1  NORMAL COURSE
         -------------

          From the date hereof until the Closing, ProFound shall:  (a) maintain
its corporate existence in good standing; (b) maintain the general character of
its business; (c) maintain in effect all of its presently existing insurance
coverage (or substantially equivalent insurance coverage); (d) preserve intact
in all material respects its business organization, preserve its goodwill and
the confidentiality of its business know how, exercise reasonable efforts to
keep available the services of its current officers and employees and preserve
its present material business relationships with its collaborators, licensors,
customers, suppliers and other Persons with which it has material business
relations; and (e) in all respects conduct its business only in the usual and
ordinary manner consistent with past practice and perform all Contracts.

    7.2  CONDUCT OF BUSINESS
         -------------------

          Without limiting the provisions of Section 7.1, from the date hereof
until the Closing (or earlier if and when this Agreement is terminated in
accordance with its Section 11), ProFound shall not, except as contemplated by
this Agreement, directly or indirectly, do, or propose to do, any of the
following without the prior written consent of Maxygen, which consent shall not
be unreasonably withheld or delayed:

        (a)  amend or otherwise modify its Organizational Documents;

        (b)  issue, sell, dispose of or Encumber or authorize the issuance,
sale, disposition or Encumbrance of, or grant or issue any option, warrant or
other right to acquire or make any agreement of the type referred to in Section
4.3, with respect to, any shares of its capital stock or any other of its
securities or any security convertible or exercisable into or exchangeable for
any such shares or securities, or alter any term of any of its outstanding
securities or make any change in its outstanding shares of capital stock or its
capitalization, whether by reason of a reclassification, recapitalization, stock
split, combination, exchange or readjustment of shares, stock dividend or
otherwise;

        (c)  Encumber any material assets or properties;

        (d)  declare, set aside, make or pay any dividend or other distribution
to any shareholder with respect to its capital stock;

        (e)  redeem, purchase or otherwise acquire any of its capital stock or
other securities;

                                       40


        (f)  increase the compensation or other remuneration or benefits payable
or to become payable to any director or executive officer, or increase the
compensation or other remuneration or benefits payable or to become payable to
any of its other employees or agents, except, with respect to such other
employees or agents only, for increases in the ordinary course of business
consistent with past practice;

        (g)  adopt or (except as otherwise required by law) amend or make any
unscheduled contribution to any employee benefit plan for or with employees, or
enter into any collective bargaining agreement;

        (h)  terminate or modify any Contract requiring future payments to or
from such party, individually or in the aggregate, in excess of DK400,000,
except for terminations of Contracts upon their expiration during such period in
accordance with their terms;

        (i)  create, incur, assume or otherwise become liable for any
indebtedness in an aggregate amount in excess of DK400,000, or guarantee or
endorse any obligation or the net worth of any Person, except for endorsements
of negotiable instruments for collection in the ordinary course of business;

        (j)  pay, discharge or satisfy any obligation or liability, absolute,
accrued, contingent or otherwise, whether due or to become due, in an aggregate
amount in excess of DK400,000, except for liabilities incurred in the ordinary
course of business prior to the date hereof where it shall not make any payment
or commitment in an aggregate amount in excess of DK800,000 (for purposes of
this Section 7.2(j), indebtedness that is created, incurred, assumed or for
which it is otherwise liable under Section 7.2(i) shall be included in
determining whether the foregoing basket amounts have been reached);

        (k)  sell, transfer, lease or otherwise dispose of any of its assets or
properties, except in the ordinary course of business consistent with past
practice and for a cash consideration equal to the fair value thereof at the
time of such sale, transfer, lease or other disposition;

        (l)  cancel, compromise, release or waive any material debt, claim or
right;

        (m)  make any loan or advance to any Person other than travel and other
similar routine advances in the ordinary course of business consistent with past
practice, or acquire any capital stock or other securities or any ownership
interest in, or substantially all of the assets of, any other business
enterprise;

                                       41


        (n)  make any material capital investment or expenditure or capital
improvement, addition or betterment, other than those specified in the list of
planned capital expenditures set forth on Exhibit 7.2(n);

        (o)  change its method of accounting or the accounting principles or
practices used in the preparation of the ProFound Financial Statements, other
than as required by GAAP;

        (p)  institute or settle any Proceeding before any Governmental
Authority relating to it or its assets or properties;

        (q)  adopt a plan of dissolution or liquidation;

        (r)  enter into any Contract, except Contracts made in the ordinary
course of business consistent with past practice;

        (s)  make any new election with respect to Taxes or any change in
current elections with respect to Taxes, or settle or compromise any federal,
state, local or foreign Tax liability or agree to an extension of a statute of
limitations;

        (t)  commence any legal proceeding or settle any legal proceeding; or

        (u)  enter into any commitment to do any of the foregoing, or take any
action that would make any of the representations or warranties of such party
contained in this Agreement untrue or incorrect in any material respect (subject
to the knowledge and materiality limitations set forth therein) or cause any
covenant, condition or agreement of such party in this Agreement not to be
complied with or satisfied in any material respect.

     In addition, without the prior written consent of Maxygen, from the date
hereof until the Closing:

             (i)   none of the ProFound Securityholders shall effect, permit or
facilitate ProFound to become a party to any Alternative Acquisition,
recapitalization, reclassification of shares, stock split, reverse stock split
or similar transaction; and

             (ii)  none of the ProFound Securityholders shall permit or
facilitate the taking of any action prohibited in (a) to (u) above.

    7.3  DANISH TAX FILING
         -----------------

        (a)  With the assistance of ProFound, the ProFound Securityholders shall
jointly prepare and file, within 10 days after the date of this Agreement, an
application to the Danish Tax Authority for a ruling that the Exchanges will be
tax deferred reorganizations pursuant to Section 13 of the Danish Act on
Taxation of Capital Gains on

                                       42


Shares (aktieavancebeskatingsloven). The application shall be submitted to
Maxygen at least five days before filing for Maxygen's review and comment. The
ProFound Securityholders shall not submit the application without Maxygen's
prior consent, which shall not be unreasonably withheld. The ProFound
Shareholders, on their behalf and on behalf of the ProFound Securityholders,
acknowledge and agree that they, and not ProFound, Maxygen or Holdings, shall be
responsible for the accuracy of the contents of the application.

        (b)  If: (i) all the conditions set forth in Section 9 except the
             --
condition set forth in Section 9.12 are satisfied, (ii) all the conditions set
forth in Section 10 except the condition set forth in Section 10.7 are satisfied
or are waived by ProFound or the Securityholder Representative, (iii) the Danish
tax authorities deny the application referenced in Section 7.3(a) by means of a
final, non-appealable written action which explains that a reason (but not
necessarily the only reason) the application was denied was the Holdings
Exchange, (iv) this Agreement is terminated after that denial by ProFound under
Section 11.2 or Section 11.4 and (v) ProFound elects to require that Maxygen
                             ---
extend a loan to ProFound by giving Maxygen a written notice to that effect
within 20 days after that termination of this Agreement, then Maxygen, in lieu
                                                         ----
of purchasing the ProFound Securities, will loan US$10 million to ProFound on
the terms and conditions set forth in the balance of this Section 7.3 and on
other reasonable and customary terms and conditions as the parties agree. The
closing and funding of that loan will occur within 20 days after ProFound gives
the notice specified in clause (v) above.

        (c)  The loan, if made, will have these principal features: The funds
loaned and all repayments will be made in, and all calculations will be based
upon, U.S. dollars. The loan will be secured by a first lien on all of
ProFound's tangible and intangible assets, it being understood that ProFound
will pay all costs (including any and all fees and Taxes) associated with
putting the lien in place and it being further understood that Maxygen's lien
will be junior to the lien currently held by Vaekstfonden on certain of
ProFound's assets. The loan will bear interest at one-year LIBOR plus 100 basis
points, with one-year LIBOR to be set for each calendar quarter or portion of
each calendar quarter during which any portion of the loan is outstanding on the
first Business Day of that calendar quarter based on the quotation for that day
published in The Wall Street Journal. The interest rate will increase to one-
             --- ---- ------ -------
year LIBOR plus 600 basis points if and for so long as the loan is in default.
Interest will be payable quarterly. All principal will be payable on the fifth
anniversary after the loan is extended. Seventy-five percent of the loan (i.e.,
                                                                          - -
US$7.5 million of the original principal plus all accrued and unpaid interest on
that principal) will be prepayable in whole or in part at the option of ProFound
without penalty or premium. Any prepayments will be applied first to accrued and
unpaid interest, and then to principal. In order to preserve Maxygen's
conversion right set forth in Section 7.3(d), the balance of the loan (i.e.,
                                                                       - -
US$2.5 million of the original principal plus all accrued and unpaid interest on
that principal) will not be prepayable, even with
                     ---

                                       43


penalty or premium, unless Maxygen so consents, which it shall be entitled not
to do in its sole discretion. During the duration of the loan, Maxygen shall be
a beneficiary of all affirmative and negative covenants that run to the benefit
of any other Person or Persons that then have outstanding loans to ProFound.

        (d)  At any time during the duration of the loan (including after its
maturity date if any portion of the loan is then in default), Maxygen, at
Maxygen's option exercisable by written notice to ProFound, may convert up to
US$2.5 million of the principal of the loan, plus all accrued and unpaid
interest on that principal, into shares of Class B ProFound Common Stock or
other equity securities of ProFound having the same rights, preferences and
privileges as shares of Class B ProFound Common Stock. The price per share of
the securities purchased on conversion will be the lower of (i) US$68 and (ii)
70 percent of the per security price at which ProFound securities are purchased
in ProFound's next round of equity financing (adjusted, if and as appropriate in
the case of clause (i) and clause (ii), to reflect stock splits, stock dividends
and similar events). The entitlements that accompany the securities purchased by
Maxygen shall include all related contractual arrangements (such as
representations, warranties, indemnities and tag-along rights) and legal
opinions received by any other Person or Persons that purchased any shares of
Class B ProFound Common Stock.

        (e)  During the duration of the loan (including after its maturity date
if any portion of the loan is then default), unless and until Maxygen has
exercised its conversion right in full, ProFound shall give Maxygen at least ten
Business Days' prior written notice of the record date for any dividend,
distribution, exchange or other event or development respecting any class or
series of ProFound securities. The purpose of this requirement is to inform
Maxygen of entitlements that may be associated with any class or series of
ProFound securities into which Maxygen might convert a portion of its loan so
that Maxygen may better determine whether to exercise its conversion right. An
example is a record date for an acquisition of ProFound in which ProFound
securityholders would receive cash or securities of another entity for their
ProFound securities.

        (f)  If the events set forth in clauses (i) through (iv) of Section
             --
7.3(b) occur but ProFound does not timely require that Maxygen loan funds to
ProFound, then, if Maxygen so elects, it may purchase up to the Danish kroner
          ----
equivalent of US$2.5 million of ProFound securities at the next closing of an
issuance of equity securities by ProFound, excluding issuances to employees
under warrants, in which (unless Maxygen waives this requirement) at least the
Danish kroner equivalent of another US$2.5 million of such equity securities are
                            -------
sold to one or more Persons who are not presently ProFound Securityholders or
affiliates of present ProFound Securityholders. The price per security, the
class and series of such securities, and the entitlements that accompany those
securities including all related contractual arrangements (such as
representations, warranties, indemnities and tag-along rights) and legal
opinions of which Maxygen is a

                                       44


beneficiary shall be the same as those received by such other "independent"
investors. The "Danish kroner equivalent" for purposes of this Section 7.3(f)
shall be based upon the "buy" exchange rate (U.S. dollars for Danish kroner)
published in The Wall Street Journal for the last Business Day before the day
             --- ---- ------ -------
that the securities purchase closes. In order to enable Maxygen properly to
assess whether it wishes to make the investment contemplated by this Section
7.3(f), ProFound shall submit all documents and disclosures to Maxygen at least
15 days before that closing.


        (g)  ProFound and the ProFound Shareholders shall be responsible for
obtaining all necessary approvals from, and making all necessary filings with,
all Governmental Authorities and other Persons to enable Maxygen to complete the
loan, pledge of assets and equity investments within the time schedules
specified in Section 7.3. By signing this Agreement, each ProFound Shareholder
gives all approvals and consents required to be made or given by it to implement
all aspects of this Section 7.3 including, for example, any and all approvals
and consents needed under ProFound's Shareholders Agreement or to amend any
Organizational Document of ProFound. All filings and approvals necessary to
enable Maxygen to exercise its conversion right shall have been obtained, to the
reasonable satisfaction of Maxygen, before Maxygen is required to fund the loan.
Maxygen shall be entitled to designate a wholly-owned direct or indirect
subsidiary of Maxygen to make the loan, equity investment or both.

    7.4  CERTAIN FILINGS
         ---------------

          ProFound, the ProFound Shareholders, Maxygen and Holdings shall
cooperate with respect to all filings, applications and notices with
Governmental Authorities and other Persons that are required to be made by
ProFound, the ProFound Shareholders, Maxygen or Holdings, including any filing
with the Danish Competition Council, to carry out the transactions contemplated
by this Agreement or that may be necessary or useful to assure that ProFound can
conduct its business after the Closing as it conducted its business before the
Closing.

    7.5  NOTIFICATION OF CERTAIN MATTERS
         -------------------------------

          Each party shall promptly notify the others of (i) the occurrence or
non-occurrence of any fact or event of which such party has knowledge that would
be reasonably likely (A) to cause any representation or warranty of such party
contained in this Agreement to be untrue or incorrect in any material respect at
any time from the date hereof to the Closing or (B) to cause any covenant,
condition or agreement of such party in this Agreement not to be complied with
or satisfied in any material respect and (ii) any failure of such party to
comply with or satisfy any covenant, condition or agreement to be complied with
or satisfied by it hereunder in any material respect; provided, however, that no
such notification shall affect any of the representations or warranties of such
party, or the right of the other party to rely thereon, or the conditions to the
obligations of the

                                       45


parties, or the remedies available hereunder, except as provided in the last
sentence of Section 11.6. The parties shall give prompt notice to the other
parties of any notice or other communication from any third Person alleging that
the consent of such third Person is or may be required in connection with the
transactions contemplated by this Agreement.

    7.6  ACCESS TO INFORMATION; CONFIDENTIALITY
         --------------------------------------

          Upon reasonable written notice, ProFound and Maxygen each shall afford
to and shall cause their respective Representatives to afford, the
Representatives of the other reasonable access, during the period prior to the
Closing, to all its Facilities, properties, assets, books, Contracts and records
and, during such period, ProFound and Maxygen each shall furnish promptly to the
other all information concerning its business, Facilities, properties, assets
and personnel as such other party may reasonably request, and each shall make
available to the other and its Representatives the appropriate individuals
(including officers, employees, accountants, counsel and other professionals)
for discussion of the other's business, Facilities, properties, assets and
personnel as either Maxygen or ProFound may reasonably request.  Each party
shall keep such information confidential in accordance with the terms of the
Confidentiality Agreement.

    7.7  REASONABLE EFFORTS; FURTHER ACTION
         ----------------------------------

        (a)  Upon the terms and subject to the conditions hereof, each of the
parties hereto shall use its reasonable efforts (exercised diligently and in
good faith) to take, or cause to be taken, all actions and to do, or cause to be
done, all other things reasonably necessary, proper or advisable to consummate
and make effective as promptly as practicable the transactions contemplated by
this Agreement, to obtain in a timely manner all necessary waivers, consents
(including, without limitation, the consent required from the Vaekstfonden in
connection with the presently outstanding loan from the Vaekstfonden),
authorizations and approvals and to effect all necessary registrations and
filings, and otherwise to satisfy or cause to be satisfied all conditions
precedent to its obligations under this Agreement.

        (b)  If, at any time after the Closing, any such further action is
necessary or desirable to carry out the purposes of this Agreement, the officers
and directors of Maxygen, Holdings and ProFound immediately prior to the Closing
are fully authorized in the name of their respective corporations or otherwise
to take, and will take, all such lawful and necessary or desirable action.

    7.8  NO SOLICITATION BY PROFOUND
         ---------------------------

          From the date hereof until the earliest of (a) the Closing, (b) the
90th day after the ProFound Securityholders file the tax application referenced
in Section 7.3(a)

                                       46


and (c) if the Danish Tax Authority denies that application, the date that is 30
days after ProFound receives that denial in writing unless the ProFound
Securityholders file an amended application before the end of that 30-day
period, in which case 15 days if and after the Danish Tax Authority denies that
amended application in writing: ProFound shall not, and shall not permit any,
officer, director, ProFound Securityholder, employee, investment banker or other
agent or Representative of ProFound, to, directly or indirectly, (i) solicit,
engage in discussions or negotiate with any Person (whether or not such
discussions or negotiations are initiated by ProFound), or take any other action
intended or designed to facilitate the efforts of any Person, other than
Maxygen, relating to the possible acquisition of ProFound (whether by way of
merger, purchase of capital stock, purchase of assets or otherwise) or any
significant portion of its capital stock or assets (with any such efforts by any
such Person to make such an acquisition referred to as an "Alternative
Acquisition"), (ii) provide information with respect to ProFound to any Person,
other than Maxygen and its Representatives, relating to a possible Alternative
Acquisition by any Person, other than Maxygen, (iii) enter into an agreement
with any Person, other than Maxygen, providing for a possible Alternative
Acquisition or (iv) make or authorize any statement, recommendation or
solicitation in support of any possible Alternative Acquisition by any Person,
other than by Maxygen. ProFound shall immediately notify Maxygen of any contact
from any Person regarding a possible Alternative Acquisition, including the name
of such Person and the content of any discussions or requests for information.

    7.9  EMPLOYMENT AGREEMENTS WITH FOUNDING SHAREHOLDERS
         ------------------------------------------------

          Maxygen or ProFound, and each Founding Shareholder shall enter into an
employment agreement in substantially the form attached hereto as Exhibit 7.9
(the "Employment Agreements").

    7.10  RELEASE AGREEMENT
          -----------------

          On or before the Closing, each ProFound Securityholder shall enter
into, and ProFound shall exercise its reasonable efforts to cause any officers,
directors and employees of ProFound who are not also ProFound Securityholders to
enter into, a release agreement in substantially the form attached hereto as
Exhibit 7.10.

    7.11  UNANIMOUS WRITTEN CONSENT OF PROFOUND SECURITYHOLDERS
          -----------------------------------------------------

          Immediately after execution of this Agreement, ProFound shall take all
reasonable action that is necessary or advisable to secure the execution and
delivery by each of the ProFound Securityholders of all Transaction Documents
necessary for

                                       47


Closing. From the date hereof until the Closing, the ProFound Securityholders
shall not sell, transfer, dispose of or Encumber any of their ProFound
Securities.

    7.12  LOCK-UP AGREEMENTS
          -------------------

          On or before the Closing, each ProFound Securityholder shall execute a
lock-up agreement preventing the transfer of any shares of Maxygen Common Stock
prior to the various time periods set forth therein.  There are four different
forms of lock-up agreement.  Exhibit 7.12 sets forth the name of each ProFound
Securityholder and the version of lock-up agreement to be executed by such
ProFound Securityholder.  Exhibits 7.12A, 7.12B, 7.12C and 7.12D are the forms
of lock-up agreements (together the "Lock-Up Agreements").

    7.13  MAXYGEN STOCK POLICIES
          ----------------------

          All continuing employees will be subject to Maxygen's insider trading
policy and guidelines applicable to similarly situated employees, as the same
may be modified from time to time.  It shall be a term of employment that each
continuing employee review the policy and comply with its terms.

    7.14  LIMITATIONS ON TRANSFERABILITY
          ------------------------------

          Each ProFound Shareholder covenants that in no event will it dispose
of any of the Maxygen securities (other than under the Put/Call Agreement signed
by that ProFound Shareholder in accordance with Section 10.8 or pursuant to
Regulation S and Rule 144 adopted by the Commission under the Securities Act or
any similar or analogous rule) unless and until (a) the ProFound Shareholder
shall have notified Maxygen of the proposed disposition and shall have furnished
Maxygen with a statement of the circumstances surrounding the proposed
disposition, and (b) if requested by Maxygen, the ProFound Shareholder shall
have furnished Maxygen with an opinion of counsel satisfactory in form and
substance to Maxygen to the effect that (x) such disposition will not require
registration under the Securities Act, (y) appropriate action necessary for
compliance with the Securities Act and any applicable state, local, or non-U.S.
law has been taken and (z) the proposed transfer satisfies all conditions set
forth in the Lock-Up Agreement executed by the ProFound Shareholder.

    7.15  CONVERSION TO APS
          -----------------

          Profound shall initiate action to convert ProFound from an A/S to an
APS, it being understood that the completion of that conversion is not a
condition to Maxygen's or Holdings' obligation to complete the Closing.

                                       48


    7.16  LOSS CARRYFORWARDS
          -------------------

          ProFound shall not take any action that would jeopardize or limit its
right or ability to make use of, and will take all actions that are necessary or
desirable to make full use of, the losses ProFound has incurred since its
inception against its future income under Danish tax law.

    7.17  RETENTION OF PROFOUND SHARES
          ----------------------------

          Maxygen or Holdings, either directly or indirectly through a direct or
indirect Subsidiary of Maxygen or Holdings, shall hold all the shares of
ProFound Common Stock acquired by Maxygen at the Closing for at least three
years after the Closing or such shorter period as may be specified in the ruling
issued by the Danish Tax Authority or as otherwise agreed by the Danish Tax
Authority.

8.  ADDITIONAL MAXYGEN OPTIONS AND BONUSES
    --------------------------------------

    8.1  OPTIONS
         -------

          Subject to the balance of this Section 8.1, within 60 days after the
Closing, Maxygen will issue options to purchase up to a total of 340,000 shares
of Maxygen Common Stock to employees of ProFound who are continuing employees.
The number of options issued to each participating employee will be determined
by the Maxygen Board of Directors in consultation with ProFound's current Chief
Executive Officers.  A tentative list is attached as Exhibit 8.1.  The options
will be issued pursuant to the Maxygen International Stock Option Plan.  Of
those options, options on 200,000 shares of Maxygen Common Stock will vest as to
50% of the shares on the third anniversary after the Closing and as to 50% on
the fourth anniversary after the Closing based on the continuing employment of
the option holder with ProFound.  The options on the other 140,000 shares of
Maxygen Common Stock will vest as to 100% of the shares of Maxygen Common Stock
on the fifth anniversary after the Closing based on the continuing employment of
the option holder with ProFound, except that those options will vest earlier if
and to the extent ProFound attains performance objectives specified by the
Maxygen Board of Directors in consultation with ProFound's current Chief
Executive Officers and the option holder is then still an employee of ProFound.
Notwithstanding anything to the contrary set forth in this Section 8.1, if any
of the persons listed on Exhibit 8.1 will not be a continuing employee of
ProFound after the Closing or has not delivered, by the Closing, the agreements
required by Section 9.9, then the 340,000-, 200,000- and 140,000-share figures
set forth in this Section 8.1 shall be reduced by the number of options shown as
allocated to those  persons on Exhibit 8.1.  Maxygen will register the shares of
common stock issuable under all the options referenced in this Section 8.1 on
Form S-8.

                                       49


    8.2  BONUSES
         -------

          Promptly after the Closing, ProFound will pay cash bonuses to those
employees of ProFound listed on Exhibit 8.2 hereto who execute the agreements
referred to in Section 9.9.  The gross amount of those bonuses, including all
applicable withholding taxes and other payments by ProFound in connection with
those bonuses, will total the Danish kroner equivalent of US$1,636,598.  The
kroner equivalents will be based upon the "buy" exchange rate for the Closing
Date as published in The Wall Street Journal.  The gross amount of the bonus
                     -----------------------
payable to each such employee is set forth on Exhibit 8.2.  Notwithstanding
anything to the contrary set forth in this Section 8.2, if any of the persons
listed on Exhibit 8.2 will not be a continuing employee of ProFound after the
Closing or has not delivered, by the Closing, the agreements required by Section
9.9, then the US$1,636,598-figure shall be reduced by the bonus figures shown
for those persons on Exhibit 8.2.

9.  CONDITIONS TO OBLIGATIONS OF MAXYGEN AND HOLDINGS
    -------------------------------------------------

     The obligations of Maxygen and Holdings under this Agreement to consummate
the Exchanges and the other transactions contemplated hereby shall be subject to
the satisfaction, at or prior to the Closing, of each of the following
conditions, any one or more of which may be waived by Maxygen and Holdings:

    9.1  REPRESENTATIONS AND WARRANTIES
         ------------------------------

          The representations and warranties of ProFound and the ProFound
Securityholders contained in this Agreement and in the agreements delivered
under Section 9.9, the ProFound Disclosure Schedule and each certificate
delivered pursuant hereto shall be complete and correct as of the date when
made, shall be deemed repeated at and as of the Closing as if made on the
Closing and, without giving effect to any qualification as to materiality (or
any variation of such term) contained in any representation or warranty, shall
then be complete and correct in all material respects.

    9.2  PERFORMANCE OF COVENANTS
         ------------------------

          ProFound and the ProFound Shareholders shall have taken all necessary
corporate or other actions to consummate the transactions contemplated hereby
and shall have performed and complied in all material respects with each
covenant, agreement and condition required by this Agreement to be performed or
complied with by it at or prior to the Closing.

                                       50


    9.3  LACK OF ADVERSE CHANGE
         ----------------------

          There shall not have occurred any incident or event which,
individually or in the aggregate, has had, or in the reasonable good faith
judgment of Maxygen is reasonably likely to result in, a ProFound Material
Adverse Effect.

    9.4  OFFICER CERTIFICATE AND SECURITYHOLDER REPRESENTATIVE certificate
         -----------------------------------------------------------------

          Maxygen and Holdings shall have received favorable certificates, dated
the Closing, signed by the Co-Chief Executive Officers of ProFound and the
Securityholder Representative as to the matters set forth in Sections 9.1, 9.2,
9.3, 9.5, 9.6, 9.14, 9.15, 9.16 and 9.17.

    9.5  NO GOVERNMENTAL OR OTHER PROCEEDING; ILLEGALITY
         -----------------------------------------------

          No Order of any Governmental Authority shall be in effect that
restrains or prohibits any transaction contemplated hereby or that would limit
or affect Maxygen's or Holdings' ownership or operation of the business or
assets of ProFound.  No Proceeding by any Governmental Authority shall be
pending or threatened against Maxygen, Holdings or ProFound or any director or
officer of any thereof or any ProFound Securityholder, that challenges the
validity or legality, or that restrains or seeks to restrain the consummation,
of the transactions contemplated hereby, or that limits or otherwise affects or
seeks to limit or otherwise affect Maxygen's or Holdings' right to own or
operate the business or assets of ProFound, or that compels or seeks to compel
Maxygen or any of its Subsidiaries to divest, abandon, license, dispose of, hold
separate or take similar action with respect to any portion of the business,
assets or properties (tangible or intangible) of Maxygen or any of its
Subsidiaries or ProFound.  No Law or Order shall be enacted, entered, enforced
or deemed applicable to either of the Exchanges or any of the other transactions
contemplated hereby which makes the consummation of either of the Exchanges or
any of the other transactions contemplated hereby illegal.

    9.6  APPROVALS AND CONSENTS
         ----------------------

          All material waivers, approvals, authorizations or Orders required to
be obtained, and all filings required to be made, by ProFound or the ProFound
Securityholders, for the authorization, execution and delivery of this Agreement
and the Transaction Documents, the consummation by it of the transactions
contemplated hereby and thereby, and the continuation in full force and effect
of any and all material rights, documents, instruments and Contracts of
ProFound, without restriction, burden or payment obligation other than those
that exist or would have existed had the transactions covered by this Agreement
and the Transaction Documents never occurred, shall have

                                       51


been obtained and made, including all consents or approvals of any Person that
may be required under any lease for real property to which ProFound is a party.
In addition, all waiting periods applicable to the consummation of the Exchanges
and the other transactions contemplated hereby shall have expired or terminated.

    9.7  OPINIONS OF COUNSEL
         -------------------

          ProFound shall have delivered to Maxygen and Holdings legal opinions
of Hjejle, Gersted & Mogensen, and Solomon Ward Seidenwurm & Smith, LLP, dated
the Closing Date and addressed to Maxygen and Holdings, as to the matters set
forth on Exhibit 9.7 hereto, it being understood that those two firms shall
allocate those opinions between them on the basis of the law of the
jurisdictions in which they practice law.

    9.8  ESCROW AGREEMENT
         ----------------

          There shall have been executed and delivered to Maxygen the Escrow
Agreement with such modifications thereto as may be agreed in accordance with
the amendment provisions set forth in the Escrow Agreement.

    9.9  AGREEMENTS WITH PROFOUND EMPLOYEES
         ----------------------------------

          Each continuing employee of ProFound who is not a signatory to this
Agreement shall have entered into, with Maxygen or ProFound as appropriate,
agreements that are reasonably satisfactory to Maxygen addressing such subjects
as non-use and confidentiality of trade secrets, the exchange of that employee's
ProFound Warrants for substitute Maxygen options (see Section 2.1),
representations and warranties analogous to those set forth in Section 5 of this
Agreement, several (but not joint and several) indemnities respecting those
representations and warranties, and the appointment of Christian Karsten Hansen
as the Securityholder Representative and (under Rule 501 adopted by the
Commission under the Securities Act) the Purchaser Representative.

    9.10  RELEASE AGREEMENTS
          ------------------
          Each of ProFound's officers, directors, securityholders and employees
shall have entered into a release agreement in substantially the form attached
hereto as Exhibit 7.10.

    9.11  LOCK-UP AGREEMENTS
          -------------------

          Each ProFound Securityholder (other than any holders of ProFound
Warrants to purchase shares of Class A ProFound Common Stock who do not receive
substitute Maxygen options) shall have entered into the applicable Lock-Up
Agreement as indicated in Exhibit 7.12.

                                       52


    9.12  TAX RULING
          ----------

          The ProFound Securityholders shall have received a ruling from the
Danish Tax Authority to the effect that their receipt of Maxygen securities in
the Maxygen Exchange will be tax deferred under Danish law and that the deferral
will continue after the Holdings Exchange without imposing additional conditions
or restrictions that would have a material adverse impact on one or more parties
to this Agreement, it being understood that the deferral shall not apply to any
cash received upon any exercise of a put or call under the agreements referenced
in Section 10.8.

    9.13  RESIGNATION OF DIRECTORS
          ------------------------

          Each of the directors of ProFound, if any, whom Maxygen requests
resign, shall have submitted his written resignation as a director of ProFound
effective as of the Closing.

    9.14  SHAREHOLDERS AGREEMENT
          ----------------------

          The Shareholders Agreement shall be terminated and all parties thereto
shall have waived all rights pursuant to such Shareholders Agreement.

    9.15  STOCK REGISTRY
          --------------

          ProFound shall have delivered to Maxygen the original stock registry,
minute books and audit records of ProFound, and Maxygen's title to all of the
ProFound Securities shall have been duly registered in the stock registry.

    9.16  MERGER LEGISLATION
          ------------------

          Denmark shall not have enacted any legislation affecting the ability
of parties to merge or combine or requiring review of any proposed merger,
combination or share exchange by any Government Authority or, if enacted, the
necessary approvals have been obtained.

    9.17  DANISH LOAN
          -----------

          ProFound shall have received the written consent of Vaekstfonden to
the continuation of the outstanding loan in accordance with its terms after the
completion of the Exchanges and, if applicable, on such additional terms as are
acceptable to Maxygen.

    9.18  PUT/CALL AGREEMENTS
          -------------------
          Christian Karsten Hansen and Jan Moller Mikkelsen shall have executed
Put/Call Agreements with Maxygen in the form of Exhibit 10.8A.

                                       53


10.  CONDITIONS TO OBLIGATIONS OF PROFOUND AND PROFOUND SHAREHOLDERS
     ---------------------------------------------------------------

          The obligations of ProFound and the ProFound Shareholders under this
Agreement to consummate the Maxygen Exchange and the other transactions
contemplated hereby shall be subject to the satisfaction, at or prior to the
Closing, of each of the following conditions, any one or more of which may be
waived by ProFound or the Securityholder Representative:

    10.1  REPRESENTATIONS AND WARRANTIES
          ------------------------------

          The representations and warranties of Maxygen and Holdings contained
in this Agreement, the Maxygen Disclosure Schedule and each certificate
delivered pursuant hereto shall be complete and correct as of the date when
made, shall be deemed repeated at and as of the Closing as if made on the
Closing and, without giving effect to any qualification as to materiality (or
any variation of such term) contained in any representation or warranty, shall
then be complete and correct in all material respects.

    10.2  PERFORMANCE OF COVENANTS
          ------------------------

          Maxygen and Holdings shall have taken all necessary corporate actions
to consummate the transactions contemplated hereby and shall have performed and
complied in all material respects with each covenant, agreement and condition
required by this Agreement to be performed or complied with by them at or prior
to the Closing.

    10.3  LACK OF ADVERSE CHANGE
          ----------------------

          There shall not have occurred any incident or event which,
individually or in the aggregate, has had a Maxygen Material Adverse Effect.

    10.4  OFFICER CERTIFICATES
          --------------------

          ProFound shall have received favorable certificates, dated the Closing
Date, signed by the Chief Executive Officer, the Chief Financial Officer or the
General Counsel of Maxygen and the President or Secretary of Holdings as to the
matters set forth in Sections 10.1, 10.2, 10.3 and 10.5.

    10.5  NO GOVERNMENTAL OR OTHER PROCEEDING
          -----------------------------------

          No Order of any Governmental Authority shall be in effect that
restrains or prohibits any transaction contemplated hereby.  No Law or Order
shall be enacted, entered, enforced or deemed applicable to the Exchanges or the
other transactions contemplated hereby which makes the consummation of the
Exchanges or the other transactions contemplated hereby illegal.

                                       54


    10.6  AGREEMENTS WITH FOUNDING SHAREHOLDERS
          -------------------------------------

          Maxygen shall have entered into the Employment Agreements with each
Founding Shareholder in substantially the form attached hereto as Exhibit 7.9.

    10.7  TAX RULING
          ----------

          The ProFound Securityholders shall have received a ruling from the
Danish Tax Authority to the effect that their receipt of Maxygen securities in
the Maxygen Exchange will be tax deferred and that the deferral will continue
after the Holdings Exchange without imposing additional conditions or
restrictions that would have a material adverse impact on one or more parties to
this Agreement, it being understood that the deferral shall not apply to any
cash received upon any exercise of a put or call under the agreements referenced
in Section 10.8.

    10.8  PUT AND PUT/CALL AGREEMENTS
          ---------------------------

          Maxygen shall have executed  Put/Call Agreements with Christian
Karsten Hansen and Jan Moller Mikkelsen in the form of Exhibit 10.8A.  Maxygen
shall also have executed Put Agreements with each holder of Class A Profound
Common Stock, other than Messrs. Hansen and Mikkelsen, in the form of Exhibit
10.8B.  The number of shares of Maxygen Common Stock to be covered by each of
those agreements and the total put and call prices payable under each of those
agreements appear on Exhibit 10.8C.

    10.9  OPINIONS OF COUNSEL
          -------------------

          Maxygen and Holdings shall have delivered to ProFound and the ProFound
Shareholders a legal opinion of Heller Ehrman White & McAuliffe LLP, dated the
Closing Date and addressed to ProFound and the ProFound Shareholders, as to the
matters set forth on Exhibit 10.9.

11.  TERMINATION OF AGREEMENT
     ------------------------

     This Agreement may be terminated at any time prior to the Closing,
notwithstanding approval thereof by ProFound, the ProFound Shareholders and
Maxygen, in the following circumstances:

    11.1  MUTUAL CONSENT
          --------------

          By mutual written consent of Maxygen, Holdings and ProFound.

                                       55


    11.2  TRANSACTION DATE
          ----------------

          If the Closing shall not have occurred by the later of (a) the close
          --                                            ----- --
of business on the 90th day after the date of this Agreement and (b) five days
                                                             ---
if and after Maxygen learns of any adverse and potentially material information
about or relating to ProFound that it did not know when this Agreement was
signed, whether it learned that information by means of a notice given under
Section 7.5 or otherwise, then Maxygen (on behalf of itself and Holdings) or
                          ----
ProFound (on behalf of itself and the ProFound Shareholders) may terminate this
Agreement, unless such failure shall be due to a material breach of any
           ------
representation or warranty, or the nonfulfillment in a material respect, and
failure to cure such nonfulfillment, of any covenant or agreement contained
herein on the part of the party seeking to terminate this Agreement or one or
more of the parties on whose behalf that party is acting (or, in the case of a
termination by Maxygen, such a breach or failure of a representation, warranty,
covenant or agreement contained in any of the agreements delivered under Section
9.9).

    11.3  FINAL ORDER OF GOVERNMENTAL AUTHORITY
          -------------------------------------

          By Maxygen or ProFound (on behalf of the ProFound Shareholders) if a
Governmental Authority shall have issued a nonappealable final Order or taken
any other action having the effect of permanently restraining, enjoining or
otherwise prohibiting either of the Exchanges or any other transaction
contemplated hereby.

    11.4  BREACH
          ------

          By Maxygen if there has been a material misrepresentation by ProFound
or any of the ProFound Securityholders, or a material breach on the part of
ProFound or any of the ProFound Securityholders of any of their warranties,
covenants or agreements set forth herein or in any of the agreements delivered
under Section 9.9, or a material failure on the part of ProFound or any of the
ProFound Securityholders to comply with any of their other obligations hereunder
or in any such agreements, or if Maxygen reasonably determines that the timely
satisfaction of any condition set forth in Section 9 has become impossible
(other than as a result of any failure on the part of Maxygen or Holdings to
comply with or perform any covenant or obligation set forth in this Agreement);
or by ProFound (on behalf of itself and the ProFound Shareholders) if there has
been a material misrepresentation by Maxygen or Holdings, or a material breach
on the part of Maxygen or Holdings of any of its warranties, covenants or
agreements set forth herein, or a material failure on the part of Maxygen or
Holdings to comply with any of its other obligations hereunder or if ProFound
reasonably determines that the timely satisfaction of any condition set forth in
Section 10 has become impossible (other than as a result of any failure on the
part of ProFound or any ProFound Securityholder to comply with or perform any
covenant or obligation set forth in this Agreement or in any of the agreements
delivered under Section 9.9); provided, however, that if such breach is

                                       56


curable by a party within 30 days, then for so long as such party continues to
exercise its reasonable efforts the other parties may not terminate this
Agreement under this Section 11.4 unless such breach is not cured within 30 days
(but no cure period shall be required for a breach that by its nature cannot be
cured).

    11.5  TERMINATION PROCEDURES
          ----------------------

          If Maxygen wishes to terminate this Agreement pursuant to Section 11.2
or Section 11.4, Maxygen shall deliver to ProFound and the Securityholder
Representative a written notice stating that Maxygen is terminating this
Agreement and setting forth a brief description of the basis on which Maxygen is
terminating this Agreement.  If ProFound wishes to terminate this Agreement
pursuant to Section 11.2 or Section 11.4, ProFound shall deliver to Maxygen a
notice, in writing, stating that ProFound is terminating this Agreement and
setting forth a brief description of the basis on which it is terminating this
Agreement.

    11.6  EFFECT OF TERMINATION
          ---------------------

          In the event of the termination of this Agreement pursuant to Section
11.1, 11.2, 11.3 or 11.4, this Agreement shall forthwith become void, except
that (i) the Confidentiality Agreement and Sections 7.3(b) through (g) (in the
case of a termination by ProFound under Section 11.2 or Section 11.4), 7.8 (in
the case of a termination by Maxygen under Section 11.2 if ProFound or a
ProFound Securityholder is then in breach of this Agreement or any of the
agreements delivered under Section 9.9, or by Maxygen under Section 11.4), 12
(in the case of a termination by Maxygen under Section 11.2 if ProFound or a
ProFound Securityholder is then in such breach, or by Maxygen under Section
11.4), 13.2, 13.4, 13.6, 13.7, 13.8, 13.9, 13.10, 13.11, 13.12, 13.13 and 13.14
of this Agreement shall survive such termination, and (ii) except as provided in
the next sentence, nothing herein shall relieve any party from liability for any
misrepresentation, breach of or failure to comply with this Agreement.
Notwithstanding the foregoing, if Maxygen proceeds with the Closing despite its
having learned about, or terminates this Agreement as a result of, an event or
circumstance that first occurs after (but not before) the date of this Agreement
and that constitutes a material breach of a representation or warranty of
ProFound or a ProFound Securityholder under this Agreement or any of the
agreements delivered under Section 9.9 but does not result from a breach of a
covenant or agreement by ProFound or a ProFound Securityholder in this Agreement
or any such agreements, then ProFound and the ProFound Securityholders shall
have no liability for that breach of representation or warranty.

                                       57


12.  INDEMNIFICATION
     ---------------

    12.1  SURVIVAL OF REPRESENTATIONS, WARRANTIES AND AGREEMENTS
          ------------------------------------------------------

        (a)  Except as otherwise provided in this Section 12, the
representations, warranties, covenants and agreements of each party under this
Agreement and the agreements delivered under Section 9.9 shall remain operative
and in full force and effect regardless of any investigation made by or on
behalf of any other party hereto, any affiliate of such party or any of their
officers, directors or Representatives, whether prior to or after the execution
of this Agreement.

        (b)  The parties' representations and warranties in this Agreement and
in any document or instrument delivered pursuant to this Agreement shall survive
the Closing and continue until 5:00 p.m., California time, on the date that is
18 months after the Closing Date (the "Expiration Date"). Notwithstanding the
preceding sentence, (i) the Tax representations and warranties set forth at
Section 4.8, the ownership representations and warranties set forth at Section
5.2, and the analogous ownership representations and warranties set forth in the
agreements delivered under Section 9.9 shall survive for the applicable statutes
of limitation; and (ii) any representation or warranty in respect of which
indemnity may be sought under Section 12.2 or 12.3 shall survive the time at
which it would otherwise terminate pursuant to the preceding sentence, if the
notice of the inaccuracy or breach thereof shall have been given to the party
against whom such indemnity may be sought prior to such time.

    12.2  OBLIGATION OF PROFOUND AND THE PROFOUND SHAREHOLDERS
          ----------------------------------------------------

          Subject to Sections 12.3 and 12.4, ProFound and each ProFound
Shareholder, jointly and severally, shall indemnify, reimburse, defend and hold
harmless Maxygen and Holdings and each of their successors and permitted assigns
and each of their respective directors, officers, employees, affiliates,
Subsidiaries, Representatives and their respective successors and permitted
assigns (each a "Maxygen Indemnitee") from and against (i) all Losses resulting
from, imposed upon, incurred or suffered by any of them, directly or indirectly,
based upon, arising out of or otherwise in respect of any inaccuracy in or any
breach of any representation, warranty, covenant or agreement of ProFound or any
ProFound Securityholder in this Agreement or in any of the agreements delivered
under Section 9.9, and (ii) all Environmental, Health, and Safety Liabilities
arising out of, or attributable or relating to, the operations of ProFound prior
to the Closing and the Facilities.  Notwithstanding the foregoing, if and after
the Closing takes place, ProFound shall have no indemnification obligations to
any Maxygen Indemnitee or any implied or other obligation to indemnify or
reimburse any ProFound Securityholder for or with respect to any amounts for
which any ProFound Securityholder indemnifies

                                       58


any Maxygen Indemnitee or relinquishes rights in the Escrow Fund. For purpose of
this Agreement, "Losses" shall mean any claims, losses, liabilities, damages,
causes of action, costs and expenses (including reasonable attorneys',
accountants', consultants' and experts' fees and expenses). The ProFound
Shareholders severally and jointly agree that the Escrow Shares shall be
available to the extent provided in this Section 12 and in the Escrow Agreement
to compensate the Maxygen Indemnitees for the forgoing Losses.

    12.3  LIMITS ON INDEMNIFICATION, REIMBURSEMENT, ETC.
          ----------------------------------------------

        (a)  No Maxygen Indemnitee shall have any right to seek indemnification,
reimbursement or defense under this Agreement or the Escrow Agreement unless and
until the total amount of all Losses and Environmental, Health, and Safety
Liabilities that would otherwise be indemnifiable hereunder and have been
incurred by the Maxygen Indemnitees as a group exceed the DK equivalent of
US$100,000 (determined on the basis of the exchange rate or rates published in
The Wall Street Journal on the date or dates that is or are 15 days after
- --- ---- ------ -------
Maxygen gives the Securityholder Representative written notice of the claim with
which the Losses and Environmental, Health, and Safety Liabilities are
associated), in which case, subject to Section 12.3(b), all Losses and
Environmental, Health, and Safety Liabilities (not just those in excess of the
DK equivalent of US$100,000) shall be fully indemnifiable. Subject to Section
12.3(b), Maxygen acknowledges that the Maxygen Indemnitees' sole right and
remedy for indemnification pursuant to this Agreement after the Closing shall be
limited to the Escrow Shares and other assets in the Escrow Fund.

        (b)  Notwithstanding the foregoing, no aspect of Section 12.3(a) shall
apply to any Losses or Environmental, Health, and Safety Liabilities based upon,
arising out of or otherwise in respect of any fraudulent breach of any
representation or warranty of ProFound or any ProFound Securityholder set forth
in this Agreement or any of the agreements delivered under Section 9.9.
Moreover, except as explained in the next sentence, the indemnification
obligations of the ProFound Shareholders shall be joint and several whether or
not Section 12.3(a) applies and whether or not, in the case of breaches of
representation and warranties, those representation and warranties are set forth
in Section 4 or 5, or any of the agreements delivered under Section 9.9.
Notwithstanding the foregoing, the indemnification obligations of Novo Nordisk
A/S shall extend beyond the Escrow Fund governed by the Escrow Agreement only to
the extent of any Losses resulting from, imposed upon, or incurred or suffered
by a Maxygen Indemnitee by virtue of a breach of any of Novo Nordisk A/S's
representations and warranties set forth in Section 5.2 of this Agreement or any
fraudulent breach of any other representation or warranty by Novo Nordisk A/S.

                                       59


    12.4  INDEMNIFICATION PROCEDURES
          --------------------------

        (a)  Notice.  Whenever any third Person claim shall arise for which
             ------
indemnification may be sought hereunder (a "Claim"), the party entitled to
indemnification (the "Maxygen Indemnitee") shall promptly give notice to the
Securityholder Representative, with respect to the Claim after the receipt by
the Maxygen Indemnitee of reliable information as to the facts constituting the
basis for the Claim; but the failure to timely give such notice shall not
relieve the Indemnitor from any obligation under this Agreement, except to the
extent, if any, that the Indemnitor is materially prejudiced thereby.

        (b)  Defense. After delivery of notice from the Maxygen Indemnitee of a
             -------
Claim, the Maxygen Indemnitee may elect to assume the defense of the Claim. If
the Maxygen Indemnitee notifies the Securityholder Representative that the
Maxygen Indemnitee is not assuming the defense of the Claim, the Securityholder
Representative shall defend the Claim. Irrespective of whether the Maxygen
Indemnitee or the Securityholder Representative defends the Claim, the cost and
the expense of that defense shall be paid from the escrow fund established under
the Escrow Agreement until that fund is exhausted. If the Maxygen Indemnitee
elects to assume the defense of the Claim, the Securityholder Representative
shall cooperate in all reasonable respects, at the Securityholder
Representative's sole cost, risk and expense, with the Maxygen Indemnitee and
its counsel in the investigation, trial, defense and any appeal arising from the
matter from which the Claim arose. If the Securityholder Representative defends
the Claim, the Maxygen Indemnitee shall cooperate in all reasonable respects
with the Securityholder Representative and its counsel in the investigation,
trial, defense and any appeal arising from the matter from which the Claim arose
and shall deliver to the Securityholder Representative or its counsel copies of
all pleadings and other information within the Maxygen Indemnitee's knowledge or
possession reasonably requested by the Securityholder Representative or its
counsel that are relevant to the defense of the subject of any such Claim. If
the Securityholder Representative defends the Claims, the Securityholder
Representative shall have the right to elect to settle any claim for monetary
damages without the Maxygen Indemnitee's consent only if the settlement includes
a complete release of the Maxygen Indemnitee. Any other settlement will be
subject to the consent of the Maxygen Indemnitee. The Securityholder
Representative may not admit any liability of the Maxygen Indemnitee or waive
any of the Maxygen Indemnitee's rights without the Maxygen Indemnitee's prior
consent. The Securityholder Representative shall not be liable for any
settlement effected without its prior consent, such consent not to be
unreasonably withheld. If any Claim results in a judgment or settlement
consistent with the terms of this Section 12.4(b), then, subject to the rules
set forth in this Section 12 that could result in indemnification "beyond" the
amounts held in the Escrow Fund (see Sections 12.1(b) and 12.3(b)), such
judgment or settlement shall be paid out of any remaining amounts in the Escrow
Fund.

                                       60


13.  GENERAL PROVISIONS
     ------------------

    13.1  FURTHER ASSURANCES
          ------------------

          Each party hereto shall execute and cause to be delivered to each
other party hereto such instruments and other documents, and shall take such
other actions, as such other party may reasonably request (prior to, at or after
the Closing) for the purpose of carrying out or evidencing any of the
transactions contemplated by this Agreement.

    13.2  CONFIDENTIALITY
          ---------------

          The parties acknowledge that Maxygen and ProFound have entered into
the Confidentiality Agreement, and that such agreement will survive the
termination of this Agreement or the consummation of the Exchanges.  Without
limiting the generality of anything contained in Section 13.6 (Public
Announcements), on and at all times after the Closing Date, each ProFound
Shareholder shall keep confidential, and shall not use or disclose to any other
Person, any non-public document or other non-public information in such ProFound
Shareholders' possession that relates to the business of Maxygen, Holdings or
ProFound.

    13.3  SEVERABILITY
          ------------

          In the event that any provision of this Agreement, or the application
of any such provision to any Person or set of circumstances, shall be determined
to be invalid, unlawful, void or unenforceable to any extent, the remainder of
this Agreement, and the application of such provision to Persons or
circumstances other than those as to which it is determined to be invalid,
unlawful, void or unenforceable, shall not be impaired or otherwise affected and
shall continue to be valid and enforceable to the fullest extent permitted by
law.

    13.4  EXPENSES
          --------

          Maxygen and ProFound will bear their respective fees, costs and
expenses incurred in connection with the preparation, execution, delivery and
performance of this Agreement, including all fees, costs and expenses of agents,
representatives, counsel and accountants.  Notwithstanding the foregoing and in
addition to all other remedies available at law or equity, if the Agreement is
terminated pursuant to Section 11.2 or 11.4, then Maxygen and Holdings (if
Maxygen's or Holdings' breach gave rise to that termination) or ProFound and the
ProFound Shareholders (if ProFound's or a ProFound Securityholder's breach gave
rise to that termination) shall pay the other party or parties by cashier's
check or wire transfer within 10 Business Days after submission of invoices in
reasonable detail all of the non-breaching party's or parties' out-of-pocket
expenses incurred in connection with the transactions contemplated by this
Agreement.

                                       61


    13.5  CONVEYANCE DOCUMENTS AND TAXES
          ------------------------------

          The parties shall cooperate in the preparation, execution and filing
of all returns, questionnaires, applications, or other documents regarding any
real or personal property transfer or any gains, sales, use, transfer, value
added, stock transfer and stamp Taxes, any transfer, recording, registration and
other fees, and any similar Taxes which become payable in connection with the
transactions contemplated hereby that are required or permitted to be filed,
whether before, on or after the Closing, and the ProFound Securityholders shall
be responsible for the payment of all such Taxes and fees.

    13.6  PUBLIC ANNOUNCEMENTS
          --------------------

          Unless required by Law, any public announcement or similar publicity
with respect to this Agreement, the Closing, the Exchanges or the other
transactions contemplated hereby will be issued, if at all, at such time and in
such manner as Maxygen determines with the concurrence of ProFound, which
concurrence shall not be unreasonably withheld or delayed by ProFound.  Unless
disclosure is consented to by Maxygen in advance or required by Law or
disclosure has otherwise already been made, ProFound shall keep this Agreement
and the transactions contemplated hereby strictly confidential and may not make
any disclosure of this Agreement or such transactions to any Person other than
its Representatives or employees who need to know such information to enable
ProFound and the ProFound Shareholders to comply with this Agreement, provided
that each such Representative or employee shall agree, for the benefit of
Maxygen, to maintain the confidentiality of such information as provided in this
Section 13.6.  ProFound and Maxygen will consult with each other concerning the
means by which ProFound's employees, customers and suppliers and other Persons
having dealings with ProFound will be informed of this Agreement, the Closing,
the Exchange and the other transactions contemplated hereby, and representatives
of Maxygen may at its option be present for any such communication.

    13.7  NOTICES
          -------

          All notices, consents, waivers, and other communications under this
Agreement must be in writing and will be deemed to have been duly given when (a)
delivered by hand (with written confirmation of receipt), (b) sent by fax (with
written confirmation of receipt), provided that a copy is mailed by registered
mail, return receipt requested, or (c) when delivered to the address, if sent by
an internationally recognized overnight delivery service (receipt requested), in
each case to the appropriate addresses or fax numbers set forth below (or to
such other address, Person's attention or fax number as a party may designate by
notice to the other parties given in accordance with this Section 13.7):

                                       62


        (a)  If to Maxygen or Holdings:
             -------------------------
        Maxygen, Inc.
        515 Galveston Drive
        Redwood City, California 94068
        U.S.A.
        Telephone No.:  001-650-298-5300
        Telecopier No.: 001-650-298-5803
        Attention:   Chief Executive Officer
                     and General Counsel

     With a copy to:
     --------------
        Heller Ehrman White & McAuliffe LLP
        2500 Sand Hill Road, Suite 100
        Menlo Park, California  94025
        U.S.A.
        Telecopier No.: 001-650-234-4299
        Telephone No.:  001-650-234-4200
        Attention:   August J. Moretti

        (b)  If to ProFound or any ProFound Shareholder:
             ------------------------------------------
          ProFound Pharma, A/S
          Ronnegade 2, 5. sal
          2100 Kobenhavn o
          Denmark
          Telecopier No.:  011-45-70-20-55-30
          Telephone No.:  011-45-39-29-84-69
          Attention:   Christian Hansen and Jan Mikkelsen

     With a copy to:
     --------------

          Hjejle, Gersted & Mogensen
          Amagertorv 24
          Denmark
          1160 Kobenhavn K
          Telecopier No.: 011-45-33-11-12-50
          Telephone No.: 011-45-33-13-42-62
          Attention:  Michael Wolff Jensen

                                       63


          Solomon Ward Seidenwurm & Smith, LLP
          1200 Wells Fargo Plaza
          401 B Street
          San Diego, California  92101
          U.S.A.
          Telecopier No.:  001-619-231-4755
          Telephone No.:   001-619-231-0303
          Attention:  Richard L. Seidenwurm

    13.8  ARBITRATION
          -----------

        (a)  Any dispute, controversy or claim arising out of this Agreement,
the Escrow Agreement or any other Transaction Document, including the
termination of any of those agreements or any alleged breach of any of those
agreements, shall be finally settled by binding arbitration as set forth in this
Section 13.8. Arbitration of any dispute, controversy or claim shall be
conducted in accordance with the Commercial Arbitration Rules of the American
Arbitration Association by three independent, neutral arbitrators appointed in
accordance with those rules. The arbitration shall be held in San Francisco,
California, U.S.A. The arbitrators shall determine what discovery shall be
permitted, consistent with the goal of limiting the cost and time which the
parties must expend for discovery, provided that the arbitrators shall permit
such discovery as they deem necessary or useful to permit an equitable and
informed resolution of the dispute. Any written evidence originally in a
language other than English shall be submitted in English translation
accompanied by the original or a true copy thereof.

        (b)  The decision or award rendered by the arbitrator shall be written
(specifically stating the arbitrator's findings of facts, as well as the reasons
upon which the arbitrator's decision is based), final and nonappealable (except
for an alleged act of corruption or fraud on the part of the arbitrator) and may
be entered in any court of competent jurisdiction for a judicial recognition of
the decision and an order of enforcement. The parties agree that, any provision
of applicable law notwithstanding, they will not request, and the arbitrator
shall have no authority to award, punitive or exemplary damages against any
party. Except as otherwise expressly provided in this Agreement, the costs of
the arbitration, including administrative and arbitrator's fees, shall be borne
50 percent by Maxygen and Holdings (jointly and severally) and: (i) if this
Agreement is terminated, 50 percent by ProFound and the ProFound Shareholders
(jointly and severally) and (ii) if the Closing occurs, by the ProFound
Shareholders (jointly and severally). Each party shall bear its own costs and
attorneys' and witness' fees incurred in connection with the arbitration.

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        (c)  A disputed performance or suspended performance pending the
resolution of the arbitration must be completed within a reasonable time
following the final decision of the arbitrators. The arbitrators shall be
directed that any arbitration subject to this Section 13.8 shall be completed
within one year from the filing of notice of a request for such arbitration. The
arbitration proceedings and the decision shall not be made public without the
joint consent of the parties. Each party shall maintain the confidentiality of
such proceedings and decision, unless otherwise permitted by Maxygen and the
Securityholder Representative. However, if advised by counsel that disclosure is
necessary or appropriate under applicable law, Maxygen shall be entitled to
disclose the proceedings and decision without the consent of any other party
after giving notice to the Securityholder Representative. Likewise, if advised
by counsel that disclosure is necessary or appropriate under applicable law, the
Securityholder Representative shall be entitled to disclose the proceedings and
decision without the consent of any other party after giving notice to Maxygen.

        (d)  Except as provided in the Escrow Agreement, any decision that
requires a monetary payment shall require such payment to be made in United
States dollars, free of any Tax or other deduction. The parties agree that the
decision shall be the sole, exclusive and binding remedy between and among them
regarding any and all disputes, controversies, claims and counterclaims
presented to the arbitrators. The interpretation and enforcement of this Section
13.8 shall be governed by the U.S. Federal Arbitration Act. Pending the
establishment of the arbitral tribunal or pending the arbitral tribunal's
determination of the merits of the controversy, either party may seek from a
court of competent jurisdiction any interim or provisional relief that may be
necessary to protect the rights or property of that party.

    13.9  FAILURE OR INDULGENCE NOT WAIVER; REMEDIES CUMULATIVE; SPECIFIC
          ---------------------------------------------------------------
          PERFORMANCE
          -----------

          No failure or delay on the part of any party hereto in the exercise of
any right hereunder shall impair such right or be construed to be a waiver of,
or acquiescence in, any breach of any representation, warranty, covenant or
agreement herein, nor shall any single or partial exercise of any such right
preclude other or further exercise thereof or of any other right.  All rights
and remedies existing under this Agreement are cumulative to, and not exclusive
of, any rights or remedies otherwise available.  The parties to this Agreement
agree that, in the event of any breach or threatened breach by any party to this
Agreement of any covenant, obligation or other provision set forth in this
Agreement for the benefit of any other party to this Agreement, subject to
Section 13.8, such other party shall be entitled (in addition to any other
remedy that may be available to it) to (a) a decree or order of specific
performance or mandamus to enforce the observance and performance of such
covenant, obligation or other provision, and (b) an injunction restraining such
breach or threatened breach.

                                       65


    13.10  ASSIGNMENTS, SUCCESSORS, AND NO THIRD-PARTY RIGHTS
           --------------------------------------------------

          No party may assign any of its rights under this Agreement without the
prior written consent of the other parties except that Maxygen may assign any of
its rights, but not its obligations, under this Agreement to any direct wholly-
owned Subsidiary of Maxygen.  Subject to the preceding sentence, this Agreement
will apply to, be binding in all respects upon, and inure to the benefit of the
successors and permitted assigns of the parties and their respective heirs and
personal representatives. Nothing expressed or referred to in this Agreement
will be construed to give any Person other than the parties to this Agreement
and the Maxygen Indemnitees any legal or equitable right, remedy or claim under
or with respect to this Agreement or any provision of this Agreement.

    13.11  SECTION HEADINGS, CONSTRUCTION
           ------------------------------

          The headings of Sections in this Agreement are provided for
convenience only and will not affect its construction or interpretation.  In
this Agreement (i) words denoting the singular include the plural and vice
versa, (ii) "it" or "its" or words denoting any gender include all genders,
(iii) the word "including" shall mean "including without limitation," whether or
not expressed, (iv) any reference to a statute shall mean the statute and any
regulations thereunder in force as of the date of this Agreement or the Closing,
as applicable, unless otherwise expressly provided, (v) any reference herein to
a Section, Schedule or Exhibit refers to a Section of or a Schedule or Exhibit
to this Agreement, unless otherwise stated, and (vi) when calculating the period
of time within or following which any act is to be done or steps taken, the date
which is the reference day in calculating such period shall be excluded and if
the last day of such period is not a Business Day, then the period shall end on
the next day that is a Business Day.  Each party acknowledges that he, she or it
has been advised and represented by counsel in the negotiation, execution and
delivery of this Agreement and accordingly agrees that if an ambiguity exists
with respect to any provision of this Agreement, such provision shall not be
construed against any party because such party or its representatives drafted
such provision.

    13.12  GOVERNING LAW
           -------------

          Except as provided in Section 13.8 and except in the case of those
corporate law matters which necessarily are governed by Danish law due to the
fact that ProFound is incorporated and doing business in Denmark, this Agreement
will be governed by the internal laws of the State of California and without
regard to principles of conflict of laws.

                                       66


    13.13  COUNTERPARTS
           ------------

          This Agreement may be executed in one or more counterparts, each of
which will be deemed to be an original copy of this Agreement and all of which,
when taken together, will be deemed to constitute one and the same agreement.

    13.14  ENTIRE AGREEMENT AND MODIFICATION
           ---------------------------------

          This Agreement supersedes all prior agreements (other than the
Confidentiality Agreement), whether written or oral, between or among the
parties with respect to its subject matter and constitutes (along with the
documents referred to in this Agreement) the entire agreement among the parties
with respect to its subject matter.  This Agreement may not be amended except by
a written agreement executed by Maxygen, Holdings, ProFound and either (i)
ProFound Shareholders holding a majority

                                       67


of the shares of ProFound Common Stock just before the Closing or (ii) the
Securityholder Representative.

     IN WITNESS WHEREOF, the parties have executed and delivered this Agreement
as of the date first written above.

                         MAXYGEN, INC.

                         By:   /s/ Russell J. Howard
                               ---------------------
                               Name:    Russell J. Howard
                               Title:   President & CEO

                         MAXYGEN HOLDINGS LTD.

                         By:   /s/ B. S. Gill
                               --------------
                               Name:    B. Gill
                               Title:   President

                         PROFOUND PHARMA A/S


                         By:     /s/ C. Braestrup, /s/ Jan Mikkelsen,
                                 ------------------------------------
                                 /s/ Christian Hansen
                                 ------------------------------------
                               Name:    C. Braestrup
                               Title:   Chairman of the Board

                               /s/ Christian Hansen
                         --------------------------------------------
                         CHRISTIAN KARSTEN HANSEN


                               /s/ Jan Mikkelsen
                         --------------------------------------------
                         JAN MOLLER MIKKELSEN


                               /s/ Tobben Halkier
                         --------------------------------------------
                         TORBEN HALKIER


                               /s/ S. Okkels
                         --------------------------------------------
                         JENS SIGURD OKKELS

                                       68


                               /s/ Anders Pedersen
                         --------------------------------------------
                         ANDERS PEDERSEN


                               /s/ Hans Schambye
                         --------------------------------------------
                         HANS THALSGARD SCHAMBYE


                               /s/ Knud Aunstrup
                         --------------------------------------------
                         KNUD AUNSTRUP




                               /s/ C. BrAEstrup
                         --------------------------------------------
                         CLAUS BRAESTRUP


                               /s/ Thue Schwartz
                         --------------------------------------------
                         THUE W. SCHWARTZ


                         BANKFORENINGERNES ERHVERVSUDVIKLINGSFORENING
                         BANKINVEST BIOMEDICINSK UDVIKLING


                         By    /s/ Finn Moefelt
                               ----------------
                         Title Managing Director
                               ------------------



                         AKTIESELSKABET BIOMEDICINSK UDVIKLING II

                         By    /s/ Jesper Zeuthen         /s/ unreadable
                               -----------------------------------------

                         Title Managing Director      CEO BankInvest Group
                               -------------------------------------------

                         NOVO NORDISK A/S


                         By    /s/ Ulrik Spork
                               ---------------

                         Title Director, Corp. Dev.
                               --------------------

                                       69


Exhibits:

2.1      Stock and Warrant Exchanges

3.1      Escrow Agreement

7.2(n)   Authorized Capital Expenditures

7.9      Employment Agreement for Founding Shareholders

7.10     Release Agreement

7.12     List of ProFound Securityholders and Lock-up Agreements

7.12A    Lock-Up Agreement (Directors)

7.12B    Lock-Up Agreement (Founders)

7.12C    Lock-Up Agreement (Employees)

7.12D    Lock-Up Agreement (BankInvest I, BankInvest II and Novo Nordisk A/S)

8.1      Additional Stock Options

8.2      Cash Bonuses

9.7      Matters to be Addressed in Opinions of ProFound's Counsel

10.8A    Put/Call Agreement

10.8B    Put Agreement

10.8C    Information About Each Put/Call and Put Agreement

10.9     Matters to be Addressed in Opinions of Maxygen's Counsel


The Registrant shall furnish a copy of any of the exhibits referred to above to
the Commission upon request.

                                       70