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                                                                       EXHIBIT 1


                                3,000,000 Shares

                         GENZYME TRANSGENICS CORPORATION

                                  Common Stock

                             UNDERWRITING AGREEMENT


                                                                 _________, 1996


PAINEWEBBER INCORPORATED
HAMBRECHT & QUIST LLC
NEEDHAM & COMPANY, INC.
  As Representatives of the
  several Underwriters
c/o PaineWebber Incorporated
  1285 Avenue of the Americas
  New York, New York  10019

Dear Sirs:

         Genzyme Transgenics Corporation, a Massachusetts corporation (the
"Company"), proposes to sell an aggregate of 3,000,000 shares (the "Firm
Shares") of the Company's Common Stock, $.01 par value per share (the "Common
Stock"), to you and to the several other Underwriters named in Schedule I hereto
(collectively, the "Underwriters"), for whom you are acting as representatives
(the "Representatives"). The Company has also agreed to grant to you and the
other Underwriters an option (the "Option") to purchase up to an additional
450,000 shares of Common Stock (the "Option Shares"), on the terms and for the
purposes set forth in Section l(b). The Firm Shares and the Option Shares are
referred to collectively herein as the "Shares".

         The initial public offering price per share for the Shares and the
purchase price per share for the Shares to be paid by the several Underwriters
shall be agreed upon by the Company and the Representatives, acting on behalf of
the several Underwriters, and such agreement shall be set forth in a separate
written instrument substantially in the form of Exhibit A hereto (the "Price
Determination Agreement"). The Price Determination Agreement may take the form
of an exchange of any standard form of written telecommunication between the
Company and the Representatives and shall specify such applicable information as
is indicated in Exhibit A hereto. The offering of the Shares will be governed by
this Agreement,
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as supplemented by the Price Determination Agreement. From and after the date of
the execution and delivery of the Price Determination Agreement, this Agreement
shall be deemed to incorporate, and, unless the context otherwise indicates, all
references contained herein to "this Agreement" and to the phrase "herein" shall
be deemed to include, the Price Determination Agreement.

         The Company confirms as follows its agreement with the Representatives
and the several other Underwriters.

         1.       Agreement to Sell and Purchase.

                  (a) On the basis of the representations, warranties and
agreements of the Company herein contained and subject to all the terms and
conditions of this Agreement, (i) the Company agrees to sell to the several
Underwriters and (ii) each of the Underwriters, severally and not jointly,
agrees to purchase from the Company, at the purchase price per share for the
Firm Shares to be agreed upon by the Representatives and the Company in
accordance with Section 1(c) hereof and set forth in the Price Determination
Agreement, the number of Firm Shares set forth opposite the name of such
Underwriter in Schedule I, plus such additional number of Firm Shares which such
Underwriter may become obligated to purchase pursuant to Section 8 hereof.
Schedule I may be attached to the Price Determination Agreement.

                  (b) Subject to all the terms and conditions of this Agreement,
the Company grants the Option to the several Underwriters to purchase, severally
and not jointly, up to 450,000 Option Shares from the Company at the same price
per share as the Underwriters shall pay for the Firm Shares. The Option may be
exercised only to cover over-allotments in the sale of the Firm Shares by the
Underwriters and may be exercised in whole or in part at any time (but not more
than once) on or before the 45th day after the date of the Price Determination
Agreement, upon written or telegraphic notice (the "Option Shares Notice") by
the Representatives to the Company no later than 12:00 noon, New York City time,
at least two and no more than five business days before the date specified for
closing in the Option Shares Notice (the "Option Closing Date") setting forth
the aggregate number of Option Shares to be purchased and the time and date for
such purchase. On the Option Closing Date, the Company will issue and sell to
the Underwriters the number of Option Shares set forth in the Option Shares
Notice, and each Underwriter will purchase such percentage of the Option Shares
as is equal to the percentage of Firm Shares that such Underwriter is
purchasing, as adjusted by the Representatives in such manner as they deem
advisable to avoid fractional shares.

                  (c) The initial public offering price per share for the Firm
Shares and the purchase price per share for the Firm Shares to be paid by the
several Underwriters shall be agreed upon and set forth in the Price
Determination Agreement. In the event that such price has not been agreed upon
and the Price Determination Agreement has not been executed by the close of
business on the fourteenth business day following the date on which the
Registration


                                      - 2 -
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Statement becomes effective, this Agreement shall terminate forthwith, without
liability of any party to any other party except that Section 6 shall remain in
effect.

   
         2. Delivery and Payment. Delivery of certificates evidencing the Firm
Shares shall be made to the Representatives for the accounts of the Underwriters
against payment of the purchase price by wire transfer to an account designated
by the Company in Federal (same-day) funds at the office of PaineWebber
Incorporated, 1285 Avenue of the Americas, New York, New York 10019. Such
payment shall be made at 10:00 a.m., New York City time, on the fourth business
day after the date of this Agreement or at such time on such other date, not 
later than ten business days after such date as may be agreed upon by the 
Company and the Representatives (such date is hereinafter referred to as the 
"Closing Date").
    

         To the extent the Option is exercised, delivery of the Option Shares
against payment by the Underwriters (in the manner specified above) will take
place at the office specified above for the Closing Date at the time and date
(which may be the Closing Date) specified in the Option Shares Notice.

         Certificates evidencing the Shares shall be in definitive form and
shall be registered in such names and in such denominations as the
Representatives shall request at least two business days prior to the Closing
Date or the Option Closing Date, as the case may be, by written notice to the
Company. For the purpose of expediting the checking and packaging of the
certificates for the Shares, the Company agrees to make such certificates
available for inspection at least 24 hours prior to the Closing Date or the
Option Closing Date, as the case may be.

         The cost of original issue tax stamps, if any, in connection with the
issuance and delivery of the Shares by the Company to the respective
Underwriters shall be borne by the Company. The Company will pay and save each
Underwriter and any subsequent holder of the Shares harmless from any and all
liabilities with respect to or resulting from any failure or delay in paying
Federal and state stamp and other transfer taxes, if any, which may be payable
or determined to be payable in connection with the original issuance or sale to
such Underwriter of the Shares.

         3.       Representations and Warranties of the Company.  The
Company represents, warrants and covenants to each Underwriter
that:

   
                  (a) A registration statement (Registration No. 333-05843) on
Form S-1 relating to the Shares, including a preliminary prospectus and such
amendments to such registration statement as may have been required to the date
of this Agreement, has been prepared by the Company under the provisions of the
Securities Act of 1933, as amended (the "Act"), and the rules and regulations
(collectively referred to as the "Rules and Regulations") of the Securities and
Exchange Commission (the "Commission") thereunder, and has been filed with the
Commission. The registration statement contains a form of preliminary
    


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prospectus to be used in connection with the offering and sale of the Shares
(the "Preliminary Prospectus"). The term "preliminary prospectus" as used herein
means a preliminary prospectus as contemplated by Rule 430 or Rule 430A ("Rule
430A") of the Rules and Regulations included at any time as part of the
registration statement. Copies of such registration statement and amendments
have been delivered to the Representatives and copies of each related
Preliminary Prospectus have been delivered to the Representatives. The term
"Registration Statement" means the registration statement as amended at the time
it becomes or became effective (the "Effective Date"), including financial
statements and all exhibits and any information deemed to be included by Rule
430A or Rule 434 of the Rules and Regulations. If the Company files a
registration statement to register a portion of the Shares and relies on Rule
462(b) of the Rules and Regulations for such registration statement to become
effective upon filing with the Commission (the "Rule 462 Registration
Statement"), then any reference to the "Registration Statement" shall be deemed
to include the Rule 462 Registration Statement, as amended from time to time.
The term "Prospectus" means a prospectus relating to the Shares (the
"Prospectus") in the form it is first filed with the Commission pursuant to Rule
424(b) of the Rules and Regulations or, if no such filing is required, the form
of final prospectus included in the Registration Statement at the Effective
Date.

   
                  (b) On the Effective Date, the date the Prospectus is first
filed with the Commission pursuant to Rule 424(b) (if required), at all times
subsequent to and including the Closing Date and, if later, the Option Closing
Date and when any post-effective amendment to the Registration Statement becomes
effective or any amendment or supplement to the Prospectus is filed with the
Commission, the Registration Statement and the Prospectus (as amended or as
supplemented if the Company shall have filed with the Commission any amendment
or supplement thereto), including the financial statements included in the
Prospectus, did or will comply with all applicable provisions of the Act and the
Rules and Regulations and will contain all statements required to be stated
therein in accordance with the Act and the Rules and Regulations. On the
Effective Date and when any post-effective amendment to the Registration
Statement becomes effective, no part of the Registration Statement or any such
amendment did or will contain any untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary in order to
make the statements therein not misleading. At the Effective Date, the date the
Prospectus or any amendment or supplement to the Prospectus is filed with the
Commission and at the Closing Date and, if later, the Option Closing Date, the
Prospectus did not or will not contain any untrue statement of a material fact
or omit to state a material fact necessary to make the statements therein, in
the light of the circumstances under which they were made, not misleading. The
foregoing representations and warranties in this Section 3(b) do not apply to
any statements or omissions made in reliance on and in conformity with
information relating to any Underwriter furnished in writing to the Company by
the Representatives specifically for inclusion in the Registration Statement or
Prospectus or any amendment or supplement thereto. For all purposes of this
Agreement, the Company acknowledges that the last two paragraphs of text on page
2 of the Prospectus, the first sentence of the second paragraph under the
heading "Underwriting" in the Prospectus and the first sentence of the fifth
paragraph under the heading "Underwriting" in the Prospectus constitute the only
information relating to any Underwriter furnished in writing to the Company by
the Representatives specifically for inclusion in the Preliminary Prospectus,
the Registration Statement or the Prospectus. The Company has not distributed
any offering material in connection with the offering or sale of the Shares
other than the
    

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Registration Statement, the preliminary prospectus, the Prospectus or any other
materials, if any, permitted by the Act.

                  (c) The only subsidiaries (as defined in the Rules and
Regulations) of the Company are the subsidiaries listed on Exhibit 21 to the
Registration Statement (the "Subsidiaries"). Each of the Company and each of its
Subsidiaries is, and at the Closing Date will be, a corporation duly organized,
validly existing and in good standing under the laws of its jurisdiction of
incorporation. Each of the Company and each of its Subsidiaries has, and at the
Closing Date will have, full power and authority to conduct all the activities
conducted by it, to own or lease all the assets owned or leased by it and to
conduct its business as described in the Registration Statement and the
Prospectus. Each of the Company and each of its Subsidiaries is, and at the
Closing Date will be, duly licensed or qualified to do business and in good
standing as a foreign corporation in all jurisdictions in which the nature of
the activities conducted by it or the character of the assets owned or leased by
it makes such licensing or qualification necessary, except where the failure to
be so licensed or qualified would not have a material adverse effect on the
business, properties, business prospects, condition (financial or otherwise), or
results of operations of the Company and its Subsidiaries, taken as a whole
(collectively, the "Business of the Company"). All of the outstanding shares of
capital stock of the Subsidiaries have been duly authorized and validly issued
and are fully paid and nonassessable and are owned by the Company free and clear
of all liens, encumbrances and claims whatsoever. Except for the stock of the
Subsidiaries and as disclosed in the Registration Statement, the Company does
not own, and at the Closing Date will not own, directly or indirectly, any
shares of stock or any other equity or long-term debt securities of any
corporation or have any equity interest in any firm, partnership, joint venture,
association or other entity. Complete and correct copies of the articles of
organization and the by-laws of the Company and each of its Subsidiaries and all
amendments thereto have been delivered to the Representatives, and no changes
therein will be made subsequent to the date hereof and prior to the Closing Date
or, if later, the Option Closing Date.

                  (d) The outstanding shares of Common Stock have been, and the
Shares to be issued and sold by the Company upon such issuance will be, duly
authorized, validly issued, fully paid and nonassessable and will not be subject
to any preemptive or similar right, and none of such shares will be subject to
any pledge, lien, security interest, charge, claim, equity or encumbrance of any
kind. The description of the capital stock of the Company in the Registration
Statement and the Prospectus is, and at the Closing Date will be, complete and
accurate in all material respects. Except as set forth in the Prospectus, the
Company does not have outstanding, and at the Closing Date will not have
outstanding, any options to purchase, or any rights or warrants to subscribe
for, or any securities or obligations convertible into, or any contracts or
commitments to issue or sell, any shares of Common Stock, any shares of capital
stock of any Subsidiary or any such warrants, convertible securities or
obligations (except options, rights or shares issued after the date as of which
information with respect thereto is given in the Prospectus pursuant to employee
benefits plans [described in the Prospectus]).


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                  (e) The financial statements and schedules included in the
Registration Statement and the Prospectus present fairly the consolidated
financial condition of the Company and of TSI Corporation as of the respective
dates thereof and the consolidated results of operations and cash flows of the
Company and TSI Corporation for the respective periods covered thereby, all in
conformity with generally accepted accounting principles applied on a consistent
basis throughout the entire period involved, except as otherwise disclosed in
the Prospectus. The pro forma financial information included in the Registration
Statement or the Prospectus (i) presents fairly in all material respects the
information shown therein and (ii) has been properly computed on the bases 
described therein. No other financial statements or schedules are required by 
the Act or the Rules and Regulations to be included in the Registration 
Statement or the Prospectus. Coopers & Lybrand, L.L.P. and Ernst & Young, 
L.L.P. (collectively, the "Accountants"), who have reported on such financial 
statements and schedules, are independent accountants with respect to the 
Company and TSI Corporation (in the case of Coopers & Lybrand L.L.P.) and TSI 
Corporation (in the case of Ernst & Young L.L.P.) as required by the Act and 
the Rules and Regulations. The statements included in the Registration 
Statement with respect to the Accountants pursuant to Rule 509 of Regulation 
S-K of the Rules and Regulations are true and correct in all material respects.
    

                  (f) The Company maintains a system of internal accounting
controls sufficient to provide reasonable assurance that (i) transactions are
executed in accordance with management's general or specific authorization; (ii)
transactions are recorded as necessary to permit preparation of financial
statements in conformity with generally accepted accounting principles and to
maintain accountability for assets; (iii) access to assets is permitted only in
accordance with management's general or specific authorization; and (iv) the
recorded accountability for assets is compared with existing assets at
reasonable intervals and appropriate action is taken with respect to any
differences.

                  (g) Subsequent to the respective dates as of which information
is given in the Registration Statement and the Prospectus and prior to the
Closing Date, except as set forth in or contemplated by the Registration
Statement and the Prospectus, (i) there has not been and will not have been any
material change in the capitalization of the Company or in the Business of the
Company arising for any reason whatsoever, (ii) neither the Company nor any of
its Subsidiaries has incurred nor will it incur any material liabilities or
obligations, direct or contingent, nor has it entered into nor will it enter
into any material transactions other than pursuant to this Agreement and the
transactions referred to herein and (iii) the Company has not and will not have
paid or declared any dividends or other distributions of any kind on any class
of its capital stock.

                  (h) The Company is not an "investment company" or an
"affiliated person" of, or "promoter" or "principal underwriter" for, an
"investment company," as such terms are defined in the Investment Company Act of
1940, as amended.


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                  (i) Except as set forth in the Registration Statement and the
Prospectus, there are no actions, suits or proceedings pending or threatened
against or affecting the Company or any of its Subsidiaries or any of their
respective officers in their capacity as such, before or by any Federal or state
court, commission, regulatory body, administrative agency or other governmental
body, domestic or foreign, wherein an unfavorable ruling, decision or finding
could materially and adversely affect the Company, any of its Subsidiaries or
the Business of the Company.

                  (j) Each of the Company and each of its Subsidiaries has, and
at the Closing Date will have, (i) all governmental licenses, permits, consents,
orders, approvals and other authorizations necessary to carry on its business,
(ii) complied in all respects with all laws, regulations and orders applicable
to it or its business and (iii) performed all of the obligations required to be
performed by it, and is not, and at the Closing Date will not be, in default,
under any indenture, mortgage, deed of trust, voting trust agreement, loan
agreement, bond, debenture, note agreement, lease, contract or other agreement
or instrument (collectively, a "contract or other agreement") to which it is a
party or by which its property is bound or affected, excluding from the
foregoing clauses (i), (ii) and (iii) those licenses, permits, consents, orders
and approvals the absence of which, and those violations, failures to perform
and defaults which, in the aggregate, would not have a material adverse effect
on the Business of the Company. To the best knowledge of the Company, no other
party under any contract or other agreement to which it is a party is in default
in any respect thereunder, except for defaults that would not have a material
adverse effect on the Business of the Company. Neither the Company nor any of
its Subsidiaries is, nor at the Closing Date will be, in violation of any
provision of its articles of organization or by-laws.

                  (k) No consent, approval, authorization or order of, or any
filing or declaration with, any court or governmental agency or body is required
for the consummation by the Company of the transactions on its part contemplated
herein, except such as have been obtained under the Act or the Rules and
Regulations and such as may be required under state securities or Blue Sky laws
or the by-laws and rules of the National Association of Securities Dealers, Inc.
(the "NASD") in connection with the purchase and distribution by the
Underwriters of the Shares to be sold by the Company or under the securities
laws of countries other than the United States.

                  (l) The Company has full corporate power and authority to
enter into this Agreement. This Agreement has been duly authorized, executed and
delivered by the Company and constitutes a valid and binding agreement of the
Company and is enforceable against the Company in accordance with the terms
hereof. The performance of this Agreement and the consummation of the
transactions contemplated hereby will not result in the creation or imposition
of any lien, charge or encumbrance upon any of the assets of the Company or any
of its Subsidiaries pursuant to the terms or provisions of, or result in a
breach or violation of any of the terms or provisions of, or constitute a
default under, or give any other party a right to terminate any of its
obligations under, or result in the acceleration of any obligation under, the
articles of organization or by-laws of the Company or any of its Subsidiaries,
any contract or other agreement to which the Company or any of its Subsidiaries
is a party or by which the


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Company or any of its Subsidiaries or any of their respective properties are
bound or affected, or violate or conflict with any judgment, ruling, decree,
order, statute, rule or regulation of any court or other governmental agency or
body applicable to the business or properties of the Company or any or its
Subsidiaries.

                  (m) Each of the Company and each of its Subsidiaries has good
and marketable title to all properties and assets described in the Prospectus as
owned by it, free and clear of all liens, charges, encumbrances or restrictions,
except such as are described in the Prospectus or are not material to the
Business of the Company. Each of the Company and each of its Subsidiaries has
valid, subsisting and enforceable leases for the properties described in the
Prospectus as leased by it, with such exceptions as are not material and do not
materially interfere with the use made and proposed to be made of such
properties by the Company and such Subsidiaries.

                  (n) There is no document or contract of a character required
to be described in the Registration Statement or the Prospectus or to be filed
as an exhibit to the Registration Statement which is not described or filed as
required. All such contracts to which the Company or any Subsidiary is a party
have been duly authorized, executed and delivered by the Company or such
Subsidiary, constitute valid and binding agreements of the Company or such
Subsidiary and are enforceable against the Company or such Subsidiary in
accordance with the terms thereof.

                  (o) No statement, representation, warranty or covenant made by
the Company in this Agreement or made in any certificate or document required by
this Agreement to be delivered to the Representatives was or will be, when made,
inaccurate, untrue or incorrect.

                  (p) Neither the Company nor any of its directors, officers or
controlling persons has taken, directly or indirectly, any action intended, or
which might reasonably be expected, to cause or result, under the Act or
otherwise, in, or which has constituted, stabilization or manipulation of the
price of any security of the Company to facilitate the sale or resale of the
Shares.

                  (q) Except as set forth in the Registration Statement and the
Prospectus, no holder of securities of the Company has rights to the
registration of any securities of the Company because of the filing of the
Registration Statement.

                  (r) The Shares have been approved for inclusion, subject to
official notice of issuance, in the National Association of Securities Dealers
Automated Quotations System/National Market System ("NASDAQ/NMS").

                  (s) Neither the Company nor any of its Subsidiaries is
involved in any material labor dispute nor, to the knowledge of the Company, is
any such dispute threatened.


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                  (t) Except as otherwise stated in the Prospectus, each of the
Company and each of its Subsidiaries owns or is licensed or otherwise possesses
adequate rights to use, all patents, patent rights, inventions, trade secrets,
know-how and proprietary techniques, including processes and substances,
trademarks, service marks, trade names and copyrights described or referred to
in the Prospectus as owned or used by it or which are necessary for the conduct
of its business as currently conducted. Except as otherwise stated in the
Prospectus, neither the Company nor any of its Subsidiaries has received any
notice of infringement of, or conflict with, asserted rights of others with
respect to any owned or licensed patents, patent rights, inventions, trade
secrets, know-how and proprietary techniques, including processes and
substances, trademarks, service marks, trade names or copyrights, which, singly
or in the aggregate, if the subject of an unfavorable decision, ruling or
finding might reasonably be expected to have a material adverse effect on the
Business of the Company.

                  (u) Neither the Company nor any of its Subsidiaries nor, to
the Company's knowledge, any employee or agent of the Company or any Subsidiary
has made any payment of funds of the Company or any Subsidiary or received or
retained any funds in violation of any law, rule or regulation or of a character
required to be disclosed in the Prospectus.

                  (v) Except as disclosed in the Registration Statement and
except as would not individually or in the aggregate have a material adverse
effect on the Business of the Company, (i) each of the Company and each of its
Subsidiaries is in material compliance with all applicable Environmental Laws,
(ii) each of the Company and each of its Subsidiaries has all permits,
authorizations and approvals required under any applicable Environmental Law and
is in material compliance with their requirements, (iii) there are no pending
or, to the knowledge of the Company, threatened Environmental Claims against the
Company or any of its Subsidiaries and (iv) to the knowledge of the Company,
there are no circumstances with respect to any of the properties or operations
of the Company or any of its Subsidiaries that could reasonably be anticipated
to form the basis of an Environmental Claim against the Company or its
Subsidiaries. For purposes of this Agreement, "Environmental Law" means any
applicable United States (or other applicable jurisdiction's) federal, state,
local or municipal statute, law, rule, regulation, ordinance, code, policy or
rule of common law and any applicable judicial or administrative interpretation
thereof including any judicial or administrative order, consent decree or
judgment, relating to the environment, health, safety or any hazardous material
or substance, exposure to which is prohibited, limited or regulated by any
governmental authority. "Environmental Claims" mean any and all administrative,
regulatory or judicial actions, suits, demands, demand letters, claims, liens,
notices of noncompliance or violation, investigations or proceedings relating in
any way to any Environmental Law.

                  (w) Each of the Technology Transfer Agreement, dated as of May
1, 1993 (the "Transfer Agreement"), between Genzyme Corporation, a Massachusetts
corporation ("Genzyme"), and the Company and the Research and Development
Agreement, dated as of May 1, 1993 (the "Development Agreement"), between
Genzyme and the Company has been duly authorized, executed and delivered by each
of the parties thereto and is enforceable


                                      - 9 -
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against Genzyme in accordance with its terms. All consents or waivers required
in order to effectively assign, transfer or sublicense to the Company Genzyme's
rights (i) to the patent applications and licenses included in the Transferred
Technology (as defined in the Transfer Agreement) including, without limitation,
those set forth in Schedule I to the Transfer Agreement and (ii) in the
Contracts (as defined in the Transfer Agreement) set forth in Schedule III to
the Transfer Agreement, have been obtained.

         4. Agreements of the Company. The Company agrees with the several
Underwriters as follows:

                  (a) The Company will not, either prior to the Effective Date
or thereafter during such period as the Prospectus is required by law to be
delivered in connection with sales of the Shares by an Underwriter or dealer,
file any amendment or supplement to the Registration Statement or the
Prospectus, unless a copy thereof shall first have been submitted to the
Representatives within a reasonable period of time prior to the filing thereof
and the Representatives shall not have objected thereto in good faith.

                  (b) The Company will use its best efforts to cause the
Registration Statement to become effective, and will notify the Representatives
promptly, and will confirm such advice in writing, (i) when the Registration
Statement has become effective and when any post-effective amendment thereto
becomes effective, (ii) of any request by the Commission for amendments or
supplements to the Registration Statement or the Prospectus or for additional
information, (iii) of the issuance by the Commission of any stop order
suspending the effectiveness of the Registration Statement or the initiation of
any proceedings for that purpose or the threat thereof, (iv) of the happening of
any event during the period mentioned in the second sentence of Section 4(e)
that in the judgment of the Company makes any statement made in the Registration
Statement or the Prospectus untrue or that requires the making of any changes in
the Registration Statement or the Prospectus in order to make the statements
therein, in the light of the circumstances under which they are made, not
misleading and (v) of receipt by the Company or any representative or attorney
of the Company of any other communication from the Commission relating to the
Company, the Registration Statement, any preliminary prospectus or the
Prospectus. If at any time the Commission shall issue any order suspending the
effectiveness of the Registration Statement, the Company will make every
reasonable effort to obtain the withdrawal of such order at the earliest
possible moment. The Company will use its best efforts to comply with the
provisions of and make all requisite filings with the Commission pursuant to
Rule 430A and to notify the Representatives promptly of all such filings.

                  (c) The Company will furnish to the Representatives, without
charge, three signed copies of the Registration Statement and of any
post-effective amendment thereto, including financial statements and schedules,
and all exhibits thereto, and, if requested, will furnish to the
Representatives, without charge, for transmittal to each of the other
Underwriters, a copy of the Registration Statement and any post-effective
amendment thereto, including financial statements and schedules but without
exhibits.


                                     - 10 -
   11
                  (d) The Company will comply with all the provisions of any
undertakings contained in the Registration Statement.

                  (e) On the Effective Date, and thereafter from time to time,
the Company will deliver to each of the Underwriters, without charge, as many
copies of the Prospectus or any amendment or supplement thereto as the
Representatives may reasonably request. The Company consents to the use of the
Prospectus or any amendment or supplement thereto by the several Underwriters
and by all dealers to whom the Shares may be sold, both in connection with the
offering or sale of the Shares and for any period of time thereafter during
which the Prospectus is required by law to be delivered in connection therewith.
If during such period of time any event shall occur which in the judgment of the
Company or counsel for the Underwriters should be set forth in the Prospectus in
order to make any statement therein, in the light of the circumstances under
which it was made, not misleading, or if it is necessary to supplement or amend
the Prospectus to comply with law, the Company will forthwith prepare and duly
file with the Commission an appropriate supplement or amendment thereto, and
will deliver to each of the Underwriters, without charge, such number of copies
of such supplement or amendment to the Prospectus as the Representatives may
reasonably request.

                  (f) Prior to any public offering of the Shares, the Company
will cooperate with the Representatives and counsel for the Underwriters in
connection with the registration or qualification of the Shares for offer and
sale under the securities or Blue Sky laws of such jurisdictions as the
Representatives may request, including, without limitation, jurisdictions
outside the United States; provided that in no event shall the Company be
obligated to qualify to do business in any jurisdiction where it is not now so
qualified or to take any action which would subject it to general service of
process in any jurisdiction where it is not now so subject.

                  (g) During the period of five years commencing on the
Effective Date, the Company will furnish to the Representatives and each other
Underwriter who may so request copies of such financial statements and other
periodic and special reports as the Company may from time to time distribute
generally to the holders of any class of its capital stock, and will furnish to
the Representatives and each other Underwriter who may so request a copy of each
annual or other periodic report it shall be required to file with the Commission
under the Securities Exchange Act of 1934, as amended (the "Exchange Act").

                  (h) The Company will make generally available to holders of
its securities as soon as may be practicable but in no event later than the last
day of the fifteenth full calendar month following the calendar quarter in which
the Effective Date falls, an earnings statement (which need not be audited but
shall be in reasonable detail) for a period of 12 months ended commencing after
the Effective Date, and satisfying the provisions of Section 11(a) of the Act
(including Rule 158 of the Rules and Regulations).

   
                  (i) Whether or not the transactions contemplated by this
Agreement are consummated or this Agreement is terminated, the Company will pay,
or reimburse if paid by
    


                                     - 11 -
   12
the Representatives, all costs and expenses incident to the performance of the
obligations of the Company under this Agreement, including, but not limited to,
costs and expenses of or relating to (i) the preparation, printing and filing of
the Registration Statement and exhibits to it, each preliminary prospectus,
Prospectus and any amendment or supplement to the Registration Statement or
Prospectus, (ii) the preparation and delivery of certificates representing the
Shares, (iii) the photocopying of this Agreement, the Agreement Among
Underwriters, any Dealer Agreements and any Underwriters' Questionnaire, (iv)
furnishing (including costs of shipping and mailing) such copies of the
Registration Statement, the Prospectus and any preliminary prospectus and all
amendments and supplements thereto, as may be requested for use in connection
with the offering and sale of the Shares, (v) the quotation of the Shares on
NASDAQ/NMS, (vi) any filings required to be made by the Underwriters with the
NASD and the fees, disbursements and other charges of counsel for the
Underwriters in connection therewith, (vii) the registration or qualification of
the Shares for offer and sale under the securities or Blue Sky laws of such
jurisdictions designated pursuant to Section 4(f), including the fees,
disbursements and other charges of counsel for the Underwriters in connection
therewith, and the preparation and photocopying of preliminary, supplemental and
final Blue Sky memoranda, (viii) counsel for the Company and (ix) the transfer
agent for the Shares.

                  (j) If this Agreement shall be terminated by the Company
pursuant to any of the provisions hereof (otherwise than pursuant to Section 8
hereof) or if for any reason the Company shall be unable to perform its
obligations hereunder, the Company will reimburse the several Underwriters for
all out-of-pocket expenses (including the fees, disbursements and other charges
of counsel for the Underwriters) reasonably incurred by them in connection
herewith.

                  (k) The Company will not at any time, directly or indirectly,
take any action intended, or which might reasonably be expected, to cause or
result in, or which will constitute, stabilization of the price of the shares of
Common Stock to facilitate the sale or resale of any of the Shares.

                  (l) The Company will apply the net proceeds from the offering
and sale of the Shares in the manner set forth in the Prospectus under "Use of
Proceeds."

   
                  (m) The Company will not, and will cause Genzyme and each of
the Company's executive officers and directors and employees previously
identified to the Company by the Representatives to enter into agreements with
the Representatives in the form set forth in Exhibit B to the effect that they
will not, for a period of [365] days after the commencement of the public
offering of the Shares, without the prior written consent of the
Representatives, offer to sell, sell, contract to sell, grant any option to sell
or otherwise dispose of or require the Company to file with the Commission a
registration statement under the Act to register any shares of Common Stock, or
securities convertible or exchangeable for shares of Common Stock or warrants or
other rights to acquire such shares (other than by the Company pursuant to
employee stock option plans or in connection with other employee incentive
compensation arrangements).
    


                                     - 12 -
   13
         5.       Conditions of the Obligations of the Underwriters. In addition
to the execution and delivery of the Price Determination Agreement, the
obligations of each Underwriter hereunder are subject to the following
conditions:

                  (a) Notification that the Registration Statement has become
effective shall be received by the Representatives not later than 3:00 p.m., New
York City time, on the date of this Agreement or at such later date and time as
shall be consented to in writing by the Representatives, and all filings
required by Rule 424 of the Rules and Regulations and Rule 430A shall have been
made.

                  (b) (i) No stop order suspending the effectiveness of the
Registration Statement shall have been issued and no proceedings for that
purpose shall be pending or threatened by the Commission, (ii) no order
suspending the effectiveness of the Registration Statement or the qualification
or registration of the Shares under the securities or Blue Sky laws of any
jurisdiction shall be in effect and no proceeding for such purpose shall be
pending before or threatened or contemplated by the Commission or the
authorities of any such jurisdiction, (iii) any request for additional
information on the part of the staff of the Commission or any such authorities
shall have been complied with to the satisfaction of the staff of the Commission
or such authorities and (iv) after the date hereof no amendment or supplement to
the Registration Statement or the Prospectus shall have been filed unless a copy
thereof was first submitted to the Representatives and the Representatives do
not object thereto in good faith, and the Representatives shall have received
certificates, dated the Closing Date and the Option Closing Date and signed by
the Chief Executive Officer or the Chairman of the Board of Directors of the
Company and the Chief Financial Officer of the Company (who may, as to
proceedings threatened, rely upon the best of their information and belief), to
the effect of clauses (i), (ii) and (iii).

                  (c) Since the respective dates as of which information is
given in the Registration Statement and the Prospectus, (i) there shall not have
been a material adverse change in the Business of the Company, whether or not
arising from transactions in the ordinary course of business, in each case,
other than as set forth in or contemplated by the Registration Statement and the
Prospectus and (ii) neither the Company nor any of its Subsidiaries shall have
sustained any material loss or interference with its business or properties from
fire, explosion, flood or other casualty, whether or not covered by insurance,
or from any labor dispute or any court or legislative or other governmental
action, order or decree, which is not set forth in the Registration Statement
and the Prospectus, if in the judgment of the Representatives, any such
development makes it impracticable or inadvisable to consummate the sale and
delivery of the Shares by the Underwriters at the initial public offering price.

                  (d) Since the respective dates as of which information is
given in the Registration Statement and the Prospectus, there shall have been no
litigation or other proceeding instituted against the Company, any of its
Subsidiaries, or any of their respective officers or directors in their
capacities as such, before or by any Federal, state or local court, commission,
regulatory body, administrative agency or other governmental body, domestic or

                                                     
                                     - 13 -
   14
foreign, in which litigation or proceeding an unfavorable ruling, decision or
finding would materially and adversely affect the Business of the Company.

                  (e) Each of the representations and warranties of the Company
contained herein shall be true and correct in all material respects at the
Closing Date, as if made at the Closing Date, and, with respect to the Option
Shares, at the Option Closing Date, as if made at the Option Closing Date, and
all covenants and agreements contained herein to be performed on the part of the
Company and all conditions contained herein to be fulfilled or complied with by
the Company at or prior to the Closing Date and, with respect to the Option
Shares, at or prior to the Option Closing Date, shall have been duly performed,
fulfilled or complied with in all material respects.

                  (f) The Representatives shall have received an opinion, dated
the Closing Date and, with respect to the Option Shares, the Option Closing
Date, and satisfactory in form and substance to counsel for the Underwriters,
(i) from Palmer & Dodge, counsel for the Company, to the effect set forth in
Exhibit C, and (ii) from Mark A. Hofer, patent and regulatory counsel for the
Company, to the effect set forth in Exhibit D.

                  (g) The Representatives shall have received an opinion, dated
the Closing Date and, with respect to the Option Shares, the Option Closing
Date, from Shearman & Sterling, counsel for the Underwriters, with respect to
the Registration Statement, the Prospectus and this Agreement, which opinion
shall be satisfactory in all respects to the Representatives.

   
                  (h) On the date of the Prospectus, each of the Accountants
shall have furnished to the Representatives a letter, dated the date of its
delivery, addressed to the Representatives and in form and substance
satisfactory to the Representatives, confirming, in the case of Coopers &
Lybrand, L.L.P., that they are independent accountants with respect to the
Company and TSI Corporation and, in the case of Ernst & Young L.L.P., that they
are independent accountants with respect to TSI Corporation, as required by the
Act and the Rules and Regulations and with respect to the financial and other
statistical and numerical information contained in the Registration Statement.
At the Closing Date and, as to the Option Shares, the Option Closing Date, each
of the Accountants shall have furnished to the Representatives a letter, dated
the date of its delivery, which shall confirm, on the basis of a review in
accordance with the procedures set forth in the letters from the Accountants,
that nothing has come to their attention during the period from the date of the
letter referred to in the prior sentence to a date (specified in the letter) not
more than five days prior to the Closing Date and the Option Closing Date, as
the case may be, which would require any change in their letter dated the date
hereof if it were required to be dated and delivered at the Closing Date and the
Option Closing Date.
    

                  (i) At the Closing Date and, as to the Option Shares, the
Option Closing Date, there shall be furnished to the Representatives an accurate
certificate, dated the date of its delivery, signed by each of the Chief
Executive Officer and the Chief Financial Officer of the Company, in form and
substance satisfactory to the Representatives, to the effect that:


                                     - 14 -
   15
                           (i) Each signer of such certificate has carefully
                  examined the Registration Statement and the Prospectus and (A)
                  as of the date of such certificate, such documents are true
                  and correct in all material respects and do not omit to state
                  a material fact required to be stated therein or necessary in
                  order to make the statements therein, in light of the
                  circumstances under which they were made, not misleading and
                  (B) since the Effective Date, no event has occurred as a
                  result of which it is necessary to amend or supplement the
                  Prospectus in order to make the statements therein not untrue
                  or misleading in any material respect.

   
                           (ii) Each of the representations and warranties of
                  the Company contained in this Agreement was, when originally
                  made, and is, at the time such certificate is delivered, true
                  and correct in all material respects.
    

                           (iii) Each of the covenants required to be performed
                  by the Company herein on or prior to the date of such
                  certificate has been duly, timely and fully performed and each
                  condition herein required to be complied with by the Company
                  on or prior to the delivery of such certificate has been duly,
                  timely and fully satisfied or fulfilled.

   
                  (j) On or prior to the Closing Date, the Representatives shall
have received the executed agreements referred to in Section 4(n).
    

                  (k) The Shares shall be qualified for sale in such
jurisdictions as the Representatives may reasonably request, and each such
qualification shall be in effect and not subject to any stop order or other
proceeding on the Closing Date and the Option Closing Date.

   
                  (l) On or prior to the Closing Date, Shares shall
be listed for quotation on the NASDAQ/NMS.
    

                  (m) The Company shall have furnished to the Representatives
such certificates, in addition to those specifically mentioned herein, as the
Representatives may have reasonably requested as to the accuracy and
completeness at the Closing Date and the Option Closing Date of any statement in
the Registration Statement or the Prospectus, as to the accuracy at the Closing
Date and the Option Closing Date of the representations and warranties of the
Company herein, as to the performance by the Company of its obligations
hereunder, or as to the fulfillment of the conditions concurrent and precedent
to the obligations hereunder of the Representatives.

                  (n) At the Closing Date and, as to the Option Shares, the
Option Closing Date, there shall be furnished to the Representatives an accurate
certificate of Genzyme, dated the date of its delivery, signed by each of the
Chief Executive Officer and the Chief Financial Officer of Genzyme, in form and
substance satisfactory to the Representatives, to the effect that:


                                     - 15 -
   16
                           (i) Each of the representations and warranties of the
                  Company contained in this Agreement were, when originally
                  made, and are, at the time such certificate is delivered, true
                  and correct in all material respects.

                           (ii) Each of the covenants required to be performed
                  by the Company herein on or prior to the date of such
                  certificate has been duly, timely and fully performed and each
                  condition herein required to be complied with by the Company
                  on or prior to the delivery of such certificate has been duly,
                  timely and fully satisfied or fulfilled.

                  (o) Concurrently with the execution and delivery of this
Agreement, there shall be furnished to the Representatives a letter agreement
from Genzyme to the effect that Genzyme shall have the joint and several
obligation, with the Company, to (A) pay, or reimburse if paid by the
Representatives, all costs and expenses set forth in Section 4(i) of this
Agreement and (B) under the circumstances set forth in Section 4(j), reimburse
the several Underwriters for all out-of-pocket expenses referred to in such
section.

         6.       Indemnification.

                  (a) The Company will indemnify and hold harmless each
Underwriter and each person, if any, who controls each Underwriter (and each
director, officer, employee and agent of each Underwriter alleged to control any
Underwriter) within the meaning of Section 15 of the Act or Section 20 of the
Exchange Act, from and against any and all losses, claims, liabilities, expenses
and damages (including any and all investigative, legal and other expenses
reasonably incurred in connection with, and any amount paid in settlement of,
any action, suit or proceeding or any claim asserted), to which they, or any of
them, may become subject under the Act, the Exchange Act or other Federal or
state statutory law or regulation, at common law or otherwise, insofar as such
losses, claims, liabilities, expenses or damages arise out of or are based on
any untrue statement or alleged untrue statement of a material fact contained in
any preliminary prospectus, the Registration Statement or the Prospectus or any
amendment or supplement to the Registration Statement or the Prospectus, or the
omission or alleged omission to state in such document a material fact required
to be stated in it or necessary to make the statements in it not misleading,
provided that the Company will not be liable to the extent that such loss,
claim, liability, expense or damage arises from the sale of the Shares in the
public offering to any person by a Underwriter and is based on an untrue
statement or omission or alleged untrue statement or omission made in reliance
on and in conformity with information relating to any Underwriter furnished in
writing to the Company by the Representatives on behalf of any Underwriter
expressly for inclusion in the Registration Statement, the Preliminary
Prospectus or the Prospectus; and provided, further, that the Company shall not
be liable to any Underwriter (or person controlling such Underwriter) under this
subsection (a) with respect to the Preliminary Prospectus to the extent that any
loss, claim, liability, expense or damage of such Underwriter results from the
fact that such Underwriter sold Shares to a person to whom there was not given
or sent, at or prior to the written confirmation of such sale, a copy of the
Prospectus or of the Prospectus as then amended or supplemented in any case
where such delivery is required by the Act if the Company had previously
furnished copies thereof to such Underwriter and the loss, claim,


                                     - 16 -
   17
liability, expense or damage of such Underwriter results from an untrue
statement or omission of a material fact contained in the Preliminary Prospectus
which was corrected in the Prospectus (or the Prospectus as amended or
supplemented). This indemnity agreement will be in addition to any liability
that the Company might otherwise have.

                  (b) Each Underwriter will indemnify and hold harmless the
Company, each person, if any, who controls the Company (and each officer,
director, employee or agent of the Company alleged to control the Company)
within the meaning of Section 15 of the Act or Section 20 of the Exchange Act,
each director of the Company and each officer of the Company who signs the
Registration Statement to the same extent as the foregoing indemnity from the
Company to each Underwriter, but only insofar as losses, claims, liabilities,
expenses or damages arise out of or are based on any untrue statement or
omission or alleged untrue statement or omission made in reliance on and in
conformity with information relating to any Underwriter furnished in writing to
the Company by the Representatives on behalf of such Underwriter expressly for
use in the Registration Statement, the Preliminary Prospectus or the Prospectus.
This indemnity will be in addition to any liability that each Underwriter might
otherwise have.

                  (c) Any party that proposes to assert the right to be
indemnified under this Section 6 will, promptly after receipt of notice of
commencement of any action against such party in respect of which a claim is to
be made against an indemnifying party or parties under this Section 6, notify
each such indemnifying party of the commencement of such action, enclosing a
copy of all papers served, but the omission so to notify such indemnifying party
will not relieve it from any liability that it may have to any indemnified party
under the foregoing provisions of this Section 6 unless, and only to the extent
that, such omission results in the forfeiture of substantive rights or defenses
by the indemnifying party. If any such action is brought against any indemnified
party and it notifies the indemnifying party of its commencement, the
indemnifying party will be entitled to participate in and, to the extent that it
elects by delivering written notice to the indemnified party promptly after
receiving notice of the commencement of the action from the indemnified party,
jointly with any other indemnifying party similarly notified, to assume the
defense of the action, with counsel satisfactory to the indemnified party, and
after notice from the indemnifying party to the indemnified party of its
election to assume the defense, the indemnifying party will not be liable to the
indemnified party for any legal or other expenses except as provided below and
except for the reasonable costs of investigation subsequently incurred by the
indemnified party in connection with the defense. The indemnified party will
have the right to employ its own counsel in any such action, but the fees,
expenses and other charges of such counsel will be at the expense of such
indemnified party unless (i) the employment of counsel by the indemnified party
has been authorized in writing by the indemnifying party, (ii) the indemnified
party has reasonably concluded (based on advice of counsel) that there may be
legal defenses available to it or other indemnified parties that are different
from or in addition to those available to the indemnifying party, (iii) a
conflict or potential conflict exists (based on advice of counsel to the
indemnified party) between the indemnified party and the indemnifying party (in
which case the indemnifying party will not have the right to direct the defense
of such action on behalf of the indemnified party) or (iv) the indemnifying
party has not in fact employed


                                     - 17 -
   18
counsel to assume the defense of such action within a reasonable time after
receiving notice of the commencement of the action, in each of which cases the
reasonable fees, disbursements and other charges of counsel will be at the
expense of the indemnifying party or parties. It is understood that the
indemnifying party or parties shall not, in connection with any proceeding or
related proceedings in the same jurisdiction, be liable for the reasonable fees,
disbursements and other charges of more than one separate firm admitted to
practice in such jurisdiction at any one time for all such indemnified party or
parties. All such fees, disbursements and other charges will be reimbursed by
the indemnifying party promptly as they are incurred. An indemnifying party will
not be liable for any settlement of any action or claim effected without its
written consent (which consent will not be unreasonably withheld).

                  (d) In order to provide for just and equitable contribution in
circumstances in which the indemnification provided for in the foregoing
paragraphs of this Section 6 is applicable in accordance with its terms but for
any reason is held to be unavailable from the Company or the Underwriters, the
Company and the Underwriters will contribute to the total losses, claims,
liabilities, expenses and damages (including any investigative, legal and other
expenses reasonably incurred in connection with, and any amount paid in
settlement of, any action, suit or proceeding or any claim asserted, but after
deducting any contribution received by the Company from persons other than the
Underwriters, such as persons who control the Company within the meaning of the
Act, officers of the Company who signed the Registration Statement and directors
of the Company, who also may be liable for contribution) to which the Company
and any one or more of the Underwriters may be subject in such proportion as
shall be appropriate to reflect the relative benefits received by the Company,
on the one hand, and the Underwriters, on the other. The relative benefits
received by the Company, on the one hand, and the Underwriters, on the other,
shall be deemed to be in the same proportion as the total net proceeds from the
offering (before deducting expenses) received by the Company bear to the total
underwriting discounts and commissions received by the Underwriters, in each
case as set forth in the table on the cover page of the Prospectus. If, but only
if, the allocation provided by the foregoing sentence is not permitted by
applicable law, the allocation of contribution shall be made in such proportion
as is appropriate to reflect not only the relative benefits referred to in the
foregoing sentence but also the relative fault of the Company, on the one hand,
and the Underwriters, on the other, with respect to the statements or omissions
which resulted in such loss, claim, liability, expense or damage, or action in
respect thereof, as well as any other relevant equitable considerations with
respect to such offering. Such relative fault shall be determined by reference
to whether the untrue or alleged untrue statement of a material fact or omission
or alleged omission to state a material fact relates to information supplied by
the Company or the Representatives on behalf of the Underwriters, the intent of
the parties and their relative knowledge, access to information and opportunity
to correct or prevent such statement or omission. The Company and the
Underwriters agree that it would not be just and equitable if contributions
pursuant to this Section 6(d) were to be determined by pro rata allocation (even
if the Underwriters were treated as one entity for such purpose) or by any other
method of allocation which does not take into account the equitable
considerations referred to herein. The amount paid or payable by an indemnified
party as a result of the loss, claim, liability, expense or damage, or action in
respect thereof, referred to above in this Section 6(d) shall be deemed to
include, for purposes of this Section 6(d), any


                                     - 18 -
   19
legal or other expenses reasonably incurred by such indemnified party in
connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this Section 6(d), no Underwriter shall be
required to contribute any amount in excess of the underwriting discounts
received by it, and no person found guilty of fraudulent misrepresentation
(within the meaning of Section 11(f) of the Act) will be entitled to
contribution from any person who was not guilty of such fraudulent
misrepresentation. The Underwriters' obligations to contribute as provided in
this Section 6(d) are several in proportion to their respective underwriting
obligations and not joint. For purposes of this Section 6(d), any person who
controls a party to this Agreement within the meaning of the Act will have the
same rights to contribution as that party, and each officer of the Company who
signed the Registration Statement will have the same rights to contribution as
the Company, subject in each case to the provisions hereof. Any party entitled
to contribution, promptly after receipt of notice of commencement of any action
against such party in respect of which a claim for contribution may be made
under this Section 6(d), will notify any such party or parties from whom
contribution may be sought, but the omission so to notify will not relieve the
party or parties from whom contribution may be sought from any other obligation
it or they may have under this Section 6(d). No party will be liable for
contribution with respect to any action or claim settled without its written
consent (which consent will not be unreasonably withheld).

                  (e) The indemnity and contribution agreements contained in
this Section 6 and the representations and warranties of the Company contained
in this Agreement shall remain operative and in full force and effect regardless
of (i) any investigation made by or on behalf of the Underwriters, (ii)
acceptance of any of the Shares and payment therefor or (iii) any termination of
this Agreement.

         7.       Termination. The obligations of the several Underwriters under
this Agreement may be terminated at any time on or prior to the Closing Date
(or, with respect to the Option Shares, on or prior to the Option Closing Date),
by notice to the Company from the Representatives, without liability on the part
of any Underwriter to the Company, if, prior to delivery of and payment for the
Firm Shares (or the Option Shares, as the case may be), in the sole judgment of
the Representatives, (i) trading in any of the equity securities of the Company
shall have been suspended by the Commission or by the NASDAQ/NMS, (ii) trading
in securities generally on the New York Stock Exchange shall have been suspended
or limited or minimum or maximum prices shall have been generally established on
such exchange, or additional material governmental restrictions, not in force on
the date of this Agreement, shall have been imposed upon trading in securities
generally by such exchange or by order of the Commission or any court or other
governmental authority, (iii) a general banking moratorium shall have been
declared by either Federal or New York State authorities or (iv) any material
adverse change in the financial or securities markets in the United States or in
political, financial or economic conditions in the United States or any outbreak
or material escalation of hostilities or declaration by the United States of a
national emergency or war or other calamity or crisis shall have occurred, the
effect of any of which is such as to make it, in the sole judgment of the
Representatives, impracticable or inadvisable to market the Shares on the terms
and in the manner contemplated by the Prospectus.


                                     - 19 -
   20
         8.       Substitution of Underwriters. If any one or more of the
Underwriters shall fail or refuse to purchase any of the Firm Shares which it or
they have agreed to purchase hereunder, and the aggregate number of Firm Shares
which such defaulting Underwriter or Underwriters agreed but failed or refused
to purchase is not more than one-tenth of the aggregate number of Firm Shares,
the other Underwriters shall be obligated, severally, to purchase the Firm
Shares which such defaulting Underwriter or Underwriters agreed but failed or
refused to purchase, in the proportions which the number of Firm Shares which
they have respectively agreed to purchase pursuant to Section 1 bears to the
aggregate number of Firm Shares which all such non-defaulting Underwriters have
so agreed to purchase, or in such other proportions as the Representatives may
specify; provided that in no event shall the maximum number of Firm Shares which
any Underwriter has become obligated to purchase pursuant to Section 1 be
increased pursuant to this Section 8 by more than one-ninth of the number of
Firm Shares agreed to be purchased by such Underwriter without the prior written
consent of such Underwriter. If any Underwriter or Underwriters shall fail or
refuse to purchase any Firm Shares and the aggregate number of Firm Shares which
such defaulting Underwriter or Underwriters agreed but failed or refused to
purchase exceeds one-tenth of the aggregate number of the Firm Shares and
arrangements satisfactory to the Representatives and the Company for the
purchase of such Firm Shares are not made within 48 hours after such default,
this Agreement will terminate without liability on the part of any
non-defaulting Underwriter or the Company for the purchase or sale of any Shares
under this Agreement. In any such case either the Representatives or the Company
shall have the right to postpone the Closing Date, but in no event for longer
than seven days, in order that the required changes, if any, in the Registration
Statement and in the Prospectus or in any other documents or arrangements may be
effected. Any action taken pursuant to this Section 8 shall not relieve any
defaulting Underwriter from liability in respect of any default of such
Underwriter under this Agreement.

         9.       Miscellaneous. Notice given pursuant to any of the provisions
of this Agreement shall be in writing and, unless otherwise specified, shall be
mailed or delivered (a) if to the Company, at the office of the Company, Five
Mountain Road, Framingham, Massachusetts 01701, Attention: President, and (b) if
to the Underwriters, to the Representatives at the offices of PaineWebber
Incorporated, 1285 Avenue of the Americas, New York, New York 10019, Attention:
Corporate Finance Department. Any such notice shall be effective only upon
receipt. Any notice under Section 7 or 8 may be made by telex or telephone, but
if so made shall be subsequently confirmed in writing.

         This Agreement has been and is made solely for the benefit of the
several Underwriters and the Company and of the controlling persons, directors
and officers referred to in Section 6, and their respective successors and
assigns, and no other person shall acquire or have any right under or by virtue
of this Agreement. The term "successors and assigns" as used in this Agreement
shall not include a purchaser, as such purchaser, of Shares from any of the
several Underwriters.

         Any action required or permitted to be taken by the Representatives
under this Agreement may be taken by them jointly or by PaineWebber
Incorporated.


                                     - 20 -
   21
         The Representatives severally represent and warrant that they have been
authorized by each of the other Underwriters to enter into this Agreement on its
behalf and to act for each of them in the manner provided herein and that this
Agreement has been duly authorized, executed and delivered by the
Representatives on behalf of the other Underwriters.

         THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO THE CONFLICT OF LAWS
PRINCIPLES OF SUCH STATE.

         This Agreement may be signed in two or more counterparts with the same
effect as if the signatures thereto and hereto were upon the same instrument.

         In case any provision in this Agreement shall be invalid, illegal or
unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby.

         The Company and the Underwriters each hereby irrevocably waive any
right they may have to a trial by jury in respect of any claim based upon or
arising out of this Agreement or the transactions contemplated hereby.

         This Agreement may not be amended or otherwise modified or any
provision hereof waived except by an instrument in writing signed by the
Representatives and the Company.

         Please confirm that the foregoing correctly sets forth the agreement
among the Company and the several Underwriters.

                                Very truly yours,


                                            GENZYME TRANSGENICS CORPORATION


                                            By:
                                               ---------------------------------
                                                  Name:
                                                  Title:


                                     - 21 -
   22
Confirmed as of the date first above mentioned:

PAINEWEBBER INCORPORATED
HAMBRECHT & QUIST LLC
NEEDHAM & COMPANY, INC.
  Acting on behalf of themselves
  and as the Representatives of
  the other several
  Underwriters named in
  Schedule I hereof.

By:  PAINEWEBBER INCORPORATED


By:
   -----------------------
     Name:
     Title:


                                     - 22 -
   23
                                   SCHEDULE I

                                  UNDERWRITERS







                                                                   Number of
                                                                  Firm Shares
Names of Underwriters                                           to be Purchased
- ---------------------                                           ---------------
                                                             

PaineWebber Incorporated

Hambrecht & Quist LLC

Needham & Company, Inc.





                                                                  ------------
         Total............................................ 
                                                                  ============

   24
                                                                       EXHIBIT A

                         GENZYME TRANSGENICS CORPORATION

                                ----------------

                          Price Determination Agreement
                                                            
                       

                                                            , 1996




PAINEWEBBER INCORPORATED
HAMBRECHT & QUIST LLC
NEEDHAM & COMPANY, INC.
  As Representatives of the several Underwriters
c/o PaineWebber Incorporated
  1285 Avenue of the Americas
  New York, New York  10019

Dear Sirs:

         Reference is made to the Underwriting Agreement, dated __________, 1996
(the "Underwriting Agreement"), between Genzyme Transgenics Corporation, a
Massachusetts corporation (the "Company"), and the several Underwriters named in
Schedule I thereto or hereto (the "Underwriters"), for whom PaineWebber
Incorporated, Hambrecht & Quist LLC and Needham & Company, Inc. are acting as
representatives (the "Representatives"). The Underwriting Agreement provides for
the purchase by the Underwriters from the Company, subject to the terms and
conditions set forth therein, of an aggregate of 3,000,000 shares (the "Firm
Shares") of the Company's common stock, par value $.01 per share. This Agreement
is the Price Determination Agreement referred to in the Underwriting Agreement.

         Pursuant to Section 1 of the Underwriting Agreement, the Company agrees
with the Representatives as follows:

         1.       The initial public offering price per share for the
                  Firm Shares shall be $____.

         2.       The purchase price per share for the Firm Shares to be paid by
                  the several Underwriters shall be $____, representing an
                  amount equal to the initial public offering price per share
                  set forth above, less $____ per share.

         The Company represents and warrants to each of the Underwriters that
the representations and warranties of the Company set forth in Section 3 of the
Underwriting Agreement are accurate as though expressly made at and as of the
date hereof.
   25
         As contemplated by the Underwriting Agreement, attached as Schedule I
is a completed list of the several Underwriters, which shall be a part of this
Agreement and the Underwriting Agreement.

         This Agreement shall be governed by and construed in accordance with
the laws of the State of New York without regard to the conflict of laws
principles of such State.

         If the foregoing is in accordance with your understanding of the
agreement between the Underwriters and the Company, please sign and return to
the Company a counterpart hereof, whereupon this instrument along with all
counterparts and together with the Underwriting Agreement shall be a binding
agreement among the several Underwriters and the Company in accordance with its
terms and the terms of the Underwriting Agreement.

                                Very truly yours,

                                            GENZYME TRANSGENICS CORPORATION


                                            By:
                                               ---------------------------------
                                                 Name:
                                                 Title:

Confirmed as of the date 
  first above mentioned:

PAINEWEBBER INCORPORATED
HAMBRECHT & QUIST LLC
NEEDHAM & COMPANY, INC.
Acting on behalf of themselves and as the Representatives of the other several
Underwriters named in Schedule I hereof.

By:  PAINEWEBBER INCORPORATED

By:
   -----------------------------
    Name:
    Title:
   26
                                                                       EXHIBIT B


                                                              , 1996




   
PAINEWEBBER INCORPORATED
HAMBRECHT & QUIST LLC
NEEDHAM & COMPANY, INC.
  As Representatives of the
  several Underwriters
c/o PaineWebber Incorporated
  1285 Avenue of the Americas
  New York, New York  10019
    

Dear Sirs:

   
         In consideration of the agreement of the several Underwriters, for
which PaineWebber Incorporated, Hambrecht & Quist LLC and Needham & Company,
Inc. (the "Representatives") intend to act as representatives, to underwrite a
proposed public offering of 3,000,000 shares of Common Stock, $.01 par value
per share (the "Common Stock"), of Genzyme Transgenics Corporation, a
Massachusetts corporation, as contemplated by a registration statement with
respect to such shares filed with the Securities and Exchange Commission on
Form S-1 (Registration No. 333-05843) (the "Registration Statement"), the
undersigned hereby agrees that the undersigned will not, for a period of [90
days] {in the case of the Company, its executive officers, directors and
certain employees} [180 days] {in the case of Genzyme} after the date of the
effective date of such Registration Statement, without the prior written
consent of the Representatives, offer to sell, sell, contract to sell, grant
any option to sell or otherwise dispose of, or require the Company to file with
the Securities and Exchange Commission a registration statement under the
Securities Act of 1933, as amended, to register any shares of Common Stock, or
securities convertible into or exchangeable for shares of Common Stock or
warrants or other rights to acquire shares of Common Stock of which the
undersigned is now, or may in the future become, the beneficial owner (within
the meaning of Rule 13d-3 under the Securities Exchange Act of 1934), except
with respect to shares of stock acquired under the Company's 1993 Employee
Stock Purchase Plan which are sold pursuant to irrevocable elections to sell
such shares on or about the date of issuance executed prior to the date hereof
{in the case of the Company's executive officers, directors and certain
employees}.
    



                                Very truly yours,

                                By:
                                   ---------------------------------------------

                                Print Name:
                                           -------------------------------------
   27
                                                                       EXHIBIT C


                               Form of Opinion of
                             Counsel to the Company


         1. Each of the Company and each of its Subsidiaries is a corporation
duly organized, validly existing and in good standing under the laws of the
jurisdiction of its incorporation. Each of the Company and each of its
Subsidiaries is duly licensed or qualified to do business and is in good
standing as a foreign corporation in all jurisdictions in which the nature of
the activities conducted by it or the character of the assets owned or leased by
it makes such licensing or qualification necessary, except where the failure to
be so licensed or qualified would not have a material adverse effect on the
business, properties, business prospects, condition (financial or otherwise), or
results of operations of the Company and its Subsidiaries, taken as a whole (the
"Business of the Company"). Each of the Company and each of its Subsidiaries has
full power and authority to conduct all the activities conducted by it, to own
or lease all the assets owned or leased by it and to conduct its business as
described in the Registration Statement and the Prospectus.

         2. The outstanding shares of Common Stock have been duly authorized and
validly issued and are fully paid and nonassessable and are not subject to any
preemptive or similar right.

         3. The Shares sold to the Underwriters pursuant to the Underwriting
Agreement have been duly authorized and validly issued by the Company and are
fully paid and nonassessable; and no holder thereof is subject to personal
liability by reason of being such a holder.

         4. The issuance of the Shares by the Company is not subject to
preemptive rights of any holder of securities of the Company.

         5. No consent, approval, authorization or order of, or any filing or
declaration with, any court or government agency or body is required in
connection with the authorization, issuance, transfer, sale or delivery of the
Shares by the Company, in connection with the execution, delivery and
performance of the Underwriting Agreement by the Company or in connection with
the taking by the Company of any action contemplated thereby, except such as
have been obtained under the Act and the Rules and Regulations and such as may
be required under the by-laws and rules of the NASD in connection with the
purchase and distribution by the Underwriters of the Shares. All references in
this opinion to the Underwriting Agreement shall include the Price Determination
Agreement.

         6. The authorized capital stock of the Company is as set forth in the
Registration Statement and the Prospectus. The description of the Company's
Common Stock contained in the Prospectus conforms to the terms thereof contained
in the Company's articles of organization.
   28
         7. The Registration Statement and the Prospectus comply in all material
respects as to form with the requirements of the Act and the Rules and
Regulations (except that we express no opinion as to financial statements,
schedules and other financial and statistical data contained in the Registration
Statement or the Prospectus).

         8. We have participated in the preparation of the Registration
Statement and the Prospectus. Except as explicitly provided herein, we have not
undertaken to verify independently the facts disclosed in the Registration
Statement and the Prospectus. However, in the course of such participation
nothing has come to our attention which has caused us to believe that (i) the
Registration Statement, at the time the Registration Statement became effective,
contained any untrue statement of a material fact or omitted to state any
material fact required to be stated therein or necessary to make the statements
therein not misleading and (ii) the Prospectus or any supplement thereto, at the
time the Prospectus or any supplement thereto was issued or on the date hereof,
contained or contains any untrue statement of a material fact or omitted or
omits to state any material fact required to be stated therein or necessary in
order to make the statements therein, in the light of the circumstances under
which they were made, not misleading (except that we express no opinion as to
financial statements, schedules and other financial or statistical data
contained in the Registration Statement or the Prospectus).

         9. The Registration Statement has become effective under the Act and,
to the best of our knowledge, no order suspending the effectiveness of the
Registration Statement has been issued and no proceeding for that purpose has
been instituted or is threatened, pending or contemplated.

         10. We have reviewed all contracts and other documents referred to in
the Registration Statement and the Prospectus, and the descriptions thereof
(insofar as such descriptions constitute a summary of the legal matters referred
to therein) are accurate in all material respects. After due inquiry, we do not
know of any contracts or other documents required to be so summarized or
disclosed or filed as an exhibit to the Registration Statement which have not
been so summarized or disclosed or filed.

         11. All descriptions in the Prospectus of statutes and regulations and,
to the best of our knowledge, of legal or governmental proceedings are accurate
and fairly present the information shown therein.

         12. The Company has full corporate power and authority to enter into
the Underwriting Agreement, and the Underwriting Agreement has been duly
authorized, executed and delivered by the Company.

         13. The execution and delivery of the Underwriting Agreement by the
Company, the consummation by the Company of the transactions therein
contemplated and the compliance by the Company with the terms of the
Underwriting Agreement do not and will not result in the creation or imposition
of any lien, charge or encumbrance upon any of the assets of the Company or any
of its Subsidiaries pursuant to the terms or provisions of, or result in a
breach or violation of any of the terms or provisions of, or constitute a
default or result in the acceleration of any obligation under, the articles of
organization or by-laws of the Company or
   29
any of its Subsidiaries, or any indenture, mortgage, deed of trust, voting trust
agreement, loan agreement, bond, debenture, note agreement or other evidence of
indebtedness, lease, contract or other agreement or instrument known to us to
which the Company or any of its Subsidiaries is a party or by which any of the
Company's or any of its Subsidiaries' properties is bound or affected, or any
judgment, ruling decree or order known to us or any statute, rule or regulation
applicable to the business or properties of the Company or any of its
Subsidiaries.

         14. Delivery of certificates for the Shares will pass valid and
marketable title thereto free and clear of any liens, encumbrances or claims to
each Underwriter that has purchased such Shares in good faith without knowledge
or reason to know of any adverse claims thereto and we are not aware, after due
inquiry, of any adverse claim with respect thereto.

         15. We know of no actions, suits or proceedings pending or threatened
against or affecting the Company or any of its Subsidiaries or any of their
respective officers in their capacities as such, before or by any Federal or
state or foreign court, commission, regulatory body, administrative agency or
other governmental body, wherein an unfavorable ruling, decision or finding
would materially and adversely affect the Company, any of its Subsidiaries or
the Business of the Company, except as set forth in or contemplated by the
Registration Statement and the Prospectus.

         16. To the best of our knowledge, neither the Company nor any of its
Subsidiaries is in violation of its articles of organization or by-laws or in
default (nor has an event occurred which with notice or lapse of time or both
would constitute a default or acceleration) in the performance of any
obligation, agreement or condition contained in any indenture, mortgage, deed of
trust, voting trust agreement, loan agreement, bond, debenture, note agreement
or other evidence of indebtedness, lease, contract or other agreement or
instrument known to us to which the Company or any of its Subsidiaries is a
party or by which they or their respective properties are bound or affected and
neither the Company nor any of its Subsidiaries is in violation of any judgment,
ruling, decree, order, franchise, license or permit known to us or any statute,
rule or regulation applicable to the business or properties of the Company or
any of its Subsidiaries, where such violation or default would have a material
adverse effect on the Business of the Company.

         17. The Company is not an "investment company" or an "affiliated
person" of, or "promoter" or "principal underwriter" for, an "investment
company," as such terms are defined in the Investment Company Act of 1940, as
amended.

         18.      The Shares have been duly authorized for quotation on
the NASDAQ National Market System upon official notice of
issuance.

         19. Each of the Transfer Agreement and the Development Agreement has
been duly authorized, executed and delivered by each of the parties thereto and
is enforceable against Genzyme in accordance with its terms, subject to
applicable bankruptcy and other similar laws affecting creditors' rights
generally and to general principles of equity. All consents or waivers required
in order to effectively assign, transfer or sublicense to the Company Genzyme's
rights (i) to the patent applications and licenses included in the Transferred
   30
Technology (as defined in the Transfer Agreement) including, without limitation,
those set forth in Schedule I to the Transfer Agreement and (ii) in the
Contracts (as defined in the Transfer Agreement) set forth in Schedule III to
the Transfer Agreement, have been obtained.

         In rendering the foregoing opinion, counsel may rely as to matters of
fact, to the extent they deem such reliance proper, on certificates of officers
of the Company and of government officials. Copies of all such certificates
shall be furnished to counsel to the Underwriters on the Closing Date. Such
counsel may state that they are not passing on matters relating to patents and
trademarks or federal or state regulation of healthcare products. Such counsel
may also state that their opinion is limited to the laws of the Commonwealth of
Massachusetts (other than the securities or Blue Sky laws thereof), the General
Corporation Law of the State of Delaware and the Federal laws of the United
States.
   31
                                                                       EXHIBIT D


                               Form of opinion of
                                  Mark A. Hofer


         1. I have studied and agree with the statements in the Prospectus under
the captions "Risk Factors -- Uncertainty Regarding Patents and Protection of
Proprietary Technology," "Risk Factors --Government Regulations," "Business --
Patents and Proprietary Rights", "Business -- Government Regulation,"
"Business--Legal Proceedings" and [ ].

   
         2. I do not know of any pending or threatened legal or governmental
proceeding relating to patents or proprietary know-how owned or used by the
Company or any of its Subsidiaries, to which the Company or any of its
Subsidiaries is a party or to which any of the properties of the Company or any
of its Subsidiaries is subject, except as disclosed in the Registration
Statement, which, if adversely decided, would have a material adverse effect on
the business, financial condition or results of operations of the Company or
any of its Subsidiaries.
    

   
         3. I have no knowledge of any infringement or alleged infringement by
the Company or any of its Subsidiaries of issued patent rights of others,
except as disclosed in the Registration Statement, which would have a material 
adverse effect on the business, financial condition or results of operations of 
the Company and its Subsidiaries, taken as a whole.
    

         4. To the best of my knowledge, each of the Company and each of its
Subsidiaries possesses all governmental licenses, permits, consents, orders,
approvals and other authorizations necessary to carry on their respective
businesses as now conducted and as described in the Prospectus, except for those
the absence of which will not have a material adverse effect on the business,
financial condition or results of operations of the Company and its
Subsidiaries, taken as a whole.