<PAGE>   1

                                                                EXHIBIT 10.43

             Confidential Materials omitted and filed separately
                 with the Securities and Exchange Commission.
                       Asterisks denote such omissions.

                                LICENSE AGREEMENT

         LICENSE AGREEMENT (this "AGREEMENT"), dated as of June 28, 1996,
between PERSEPTIVE BIOSYSTEMS, INC., a Delaware corporation, and its wholly
owned subsidiaries, PERSEPTIVE TECHNOLOGIES II CORPORATION ("PTC-II"), a
Delaware corporation, and VESTEC CORPORATION, a Texas corporation ("VESTEC"),
(collectively, "PERSEPTIVE"), and CHEMGENICS PHARMACEUTICALS INC., a Delaware
corporation ("CHEMGENICS"). All capitalized terms shall have the respective
meanings set forth in Section 1 hereof and Schedule A hereto.

                                R E C I T A L S :

         A. PerSeptive and ChemGenics are parties to a Master Agreement dated as
of May __, 1996 (the "MASTER AGREEMENT").

         B. PerSeptive is the owner or licensee of rights in certain Technology
and certain patent rights relating thereto.

         C. PerSeptive is willing to grant to ChemGenics and ChemGenics desires
to acquire from PerSeptive, a non-exclusive worldwide license within the Field,
under such Technology and patent rights for the purpose of allowing ChemGenics
to discover drugs and develop, market, sell, import and/or deliver, certain
Products and Services.

         NOW, THEREFORE, in consideration of the mutual covenants set forth
herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, and in order to induce each other
to enter into the Master Agreement, PerSeptive and ChemGenics hereby agree as
follows:

         1.       DEFINITIONS.

                  1.1. DEFINITIONS. As used herein, capitalized terms shall have
the respective meanings set forth below and in Schedule A attached hereto, which
is incorporated by this reference as though fully set forth herein.

                  1.2. SINGULAR AND PLURAL. Singular and plural forms, as the
case may be, of terms defined herein shall have correlative meanings.

         2.       GRANT OF LICENSES.

                  2.1. GRANT OF LICENSE TO CHEMGENICS.

                           2.1.1. PERSEPTIVE PATENT RIGHTS AND ASSOCIATED
TECHNOLOGY.

(a) Subject to the terms and conditions of this Agreement, PerSeptive hereby
grants to ChemGenics a non-exclusive, irrevocable, worldwide, royalty-free fully
paid right and
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                                      - 2 -



license, terminable only as set forth in Sections 9.2, 9.3 or 9.4, solely within
the Field, to (a) develop, make, have made, use, offer to sell, sell and import
any Products and/or to provide any Services the use, manufacture, sale or
provision of which is Covered By one or more claims of the PerSeptive Patent
Rights and (b) develop, make, have made, use, offer to sell, sell and import any
Products and/or provide any Services incorporating, utilizing, manufactured
using, based upon, arising out of, or derived from the Associated Technology. In
addition, to the extent that ChemGenics acquires, or acquires the right to use,
any PerSeptive products (including any prototypes or "beta-test" products)
pursuant to this Agreement, the Master Agreement any other agreement executed in
connection therewith, ChemGenics shall have all rights which ChemGenics would
have under PerSeptive's standard User Licenses to use such products as if
ChemGenics were a customer of PerSeptive or a purchaser in the market of such
PerSeptive products. Notwithstanding the foregoing or any other provision of
this Agreement, neither ChemGenics nor any Partner shall have any right or
license to the Licensed Technology which is PerSeptive Patent Rights or
Confidential Information of PerSeptive to develop, make, have made, offer to
sell, sell or otherwise distribute Products that are Tools which are Covered By
PerSeptive Patent Rights or which are based upon, arise out of, use or are
derived from Licensed Technology which is Confidential Information of
PerSeptive; and ChemGenics shall not have the right to grant sublicenses of the
Licensed Technology except to the extent necessary to permit any Partner of
ChemGenics to conduct research and/or development within the Field on such
Partner's premises pursuant to the terms of such Partner's agreement with
ChemGenics or to manufacture and sell any drugs developed in conjunction with
ChemGenics pursuant to such agreement and subject to the confidentiality and
non-use obligations of Section 5.3 hereof; provided that no such Partner shall
thereby have any right or license to (i) make, have made, offer to sell, sell,
license or otherwise distribute any products or to deliver any services to any
Person the use of which is Covered By the PerSeptive Patent Rights or which
incorporates, utilizes, is manufactured using, is based upon, arises out of, or
is derived from the Associated Technology except for drugs developed in
conjunction with ChemGenics; or (ii) practice the Licensed Technology on or in
connection with the making, use or operation of any Tools unless such right has
been acquired from PerSeptive outside of this Agreement.

         (b) Subject to the terms and conditions of this Agreement, PerSeptive
further grants to ChemGenics an exclusive, irrevocable, worldwide, royalty free
fully paid right and license, terminable only as set forth in Section 9.3, to
all PerSeptive Patent Rights and Associated Technology, that (i) arise out of
the research projects listed on Schedule D which were part of the Drug Discovery
Program (as defined in the Master Agreement), and (ii) specifically relate to
the potential drugs, drug candidates and drug targets which were the subject of
those research projects (the foregoing PerSeptive Patent Rights and Associated
Technology being called the "Discovery Program Technology"), to develop, make,
have made, use, offer to sell, sell and import such drugs, drug candidates or
drug targets. PerSeptive expressly reserves all rights (subject to the license
in the Field granted in Section 2.1.1(a)) to the Discovery Program Technology
for all uses other than as drugs, drug candidates, or drug targets; provided,
however, that PerSeptive shall not offer for sale, sell or distribute (or
license any Person to do so) any compound or molecule which is part of the
Discovery Program Technology for any use which would interfere with or adversely
affect (i) ChemGenics' ability to market a compound or molecule which is part of
the Discovery
<PAGE>   3
                                      - 3 -



Program Technology as a drug, drug candidate, or drug target or (ii) ChemGenics'
profitability from such marketing; provided, further, that the restriction in
the preceding clause shall not restrict PerSeptive's rights in the PerSeptive
Field.

         (c) For the avoidance of doubt, it is acknowledged and agreed that the
foregoing rights and licenses include the right to (i) develop, make, have made,
use, offer to sell, sell and import Products which are diagnostic analytes or
reagents or targets which are not Covered By PerSeptive Patent Rights or which
are not Licensed Technology which is Confidential Information for specific
diseases or patient conditions and Products for diagnostic use which incorporate
such analytes or reagents or targets, and (ii) grant rights to Partners to do
so.

                           2.1.2. RESTRICTIONS ON FUTURE LICENSES. PerSeptive
agrees that, without the prior consent of ChemGenics, it shall not (a) utilize
the Licensed Technology in the Field or (b) grant a license or other right to
any third party to do the same, provided, however, that, without ChemGenics'
consent, PerSeptive may grant to purchasers of its products restricted or
unrestricted User Licenses within or outside the Field and may provide and
perform and permit others to perform pre- and post-sale service, consistent with
PerSeptive's current practice, related to such products within or outside the
Field. Except for the licenses and rights granted by Section 2.1.1 hereof and
the restrictions contained in the preceding sentence, PerSeptive reserves the
exclusive (against ChemGenics and all other Persons) worldwide right to develop
and use, and to license to any Person and authorize further sublicenses with
respect to, the Associated Technology and the PerSeptive Patent Rights and to
develop, make, have made, use, offer to sell, sell and import products and/or
provide services utilizing or Covered By the Licensed Technology within or
outside of the Field.

                           2.1.3. THIRD-PARTY TRANSFERS OF RIGHTS TO PERSEPTIVE.
In the event that PerSeptive has licensed from a third party any of the Licensed
Technology licensed to ChemGenics pursuant to Section 2.1.1 hereof, PerSeptive
hereby grants to ChemGenics a non-exclusive license of such Licensed Technology
to the extent that, and for as long as, PerSeptive can provide such rights and
subject to any royalty obligations as hereinafter provided. With respect to any
patent rights or Technology granted or assigned to PerSeptive in the future
pursuant to an agreement with any Person other than ChemGenics, the license
granted to ChemGenics hereunder shall be no greater in scope than the rights
that PerSeptive has a right to grant under such agreement and shall be otherwise
subject to any obligations assumed by PerSeptive in consideration of the grant
or assignment of such rights to PerSeptive which are to be sublicensed to
ChemGenics. PerSeptive agrees that in negotiating any such agreement with a
Person other than ChemGenics, it will use reasonable efforts to obtain the right
to fully license ChemGenics hereunder for all such patent rights or Technology
in the Field. In the event of any conflict or inconsistency between any
provision of any such sublicense to ChemGenics and any provisions of Sections
5.3, 5.4, 7, 8 or 13 of this Agreement, the said provisions of this Agreement
shall prevail. ChemGenics shall not take any action, or fail to take any action
within its control, that would constitute or give rise to a breach or other
violation by PerSeptive of any such agreement. Without limiting the foregoing,
to the extent that the sale or other action by ChemGenics or its permitted
<PAGE>   4
                                      - 4 -



sublicensees of Products would give rise to a royalty or other payment
obligation under any such agreement, ChemGenics shall pay and require its
sublicensees to pay such amount. In the event that PerSeptive acquires for value
from a Person other than ChemGenics after the date hereof during the period this
Agreement is in effect patent rights or Technology useful in development of
Products or Services in the Field, nothing in this Agreement or any other
agreement between the parties, other than Section 2.1.2 hereof, shall be
construed to prohibit or restrict PerSeptive from continuing to manufacture and
sell any product so acquired or from selling, licensing, or developing the
acquired patent rights or Technology and any successor product or improved
product so developed, and any such patent rights or Technology acquired after
the date of this Agreement shall be licensed non-exclusively to ChemGenics in
the Field subject to the terms of Sections 2.1.1 and 2.1.2 and this Section
2.1.3.

                  2.2. NO RESTRICTIONS ON PERSEPTIVE'S OTHER BUSINESSES. Nothing
in this Agreement shall be interpreted to preclude PerSeptive or any of its
Affiliates or licensees or sublicensees from engaging in its current business of
designing, manufacturing, marketing, selling and licensing products and
instrumentation systems for the purification, synthesis, sequencing or analysis
of biomolecules and providing tools to the life sciences industry, or from
making, selling or licensing, to any Person and for any purpose within or
outside the Field, instruments, equipment, machinery, apparatus, devices, media,
reagents, compounds, resins, activators, linkers, particles, supports and other
materials and substances (including, without limitation, oligomers, peptides and
other molecules), tools or other products (and systems comprising the foregoing)
or from providing any services outside the Field or any pre- and post-sale
services, consistent with PerSeptive's current practice, related to the sale or
license of the foregoing within the Field for or capable of, biomolecular
purification, diagnosis, synthesis, sequencing or analysis incorporating,
utilizing, manufactured using, based upon, arising out of, or derived from any
Licensed Technology, including without limitation POROS(R) media, chromatography
columns, separation devices, computer workstations, mass spectrometers,
synthesizers, sequencers and other instruments and equipment.

                  2.3 NO RESTRICTIONS ON CHEMGENICS DRUG COMMERCIALIZATION.
Nothing in this Agreement shall prevent ChemGenics or its Partners from
developing, making, having made, selling, licensing or otherwise commercializing
and distributing (i) any drugs or drug candidates discovered by ChemGenics or
its Partners with or without the use of the Licensed Technology, and (ii) any
Tools which are not Covered By PerSeptive Patent Rights or which do not
incorporate, utilize or arise out of and are not manufactured, using and are not
based upon or derived from Associated Technology which is Confidential
Information. The foregoing shall not relieve ChemGenics from its obligations
under the Non-Competition Agreement (as defined in the Master Agreement).

                  2.4. RIGHTS TO JOINTLY DEVELOPED INVENTIONS.

                           2.4.1. JOINT INVENTIONS JOINTLY OWNED. All right,
title and interest to any inventions or improvements within or outside the Field
developed jointly by the Parties shall be the joint property of the Parties.
Joint inventorship shall be determined in
<PAGE>   5
             Confidential Materials omitted and filed separately
                 with the Securities and Exchange Commission.
                       Asterisks denote such omissions.

                                      - 5 -


accordance with United States Patent Law; provided however, that for the
avoidance of doubt, it is acknowledged and agreed that the use or incorporation
by ChemGenics of Licensed Technology in the making of an invention or
improvement will not, by itself, make such invention or improvement jointly
owned.

                           2.4.2. JOINT INVENTIONS IN THE FIELD. If ChemGenics
shall determine that any joint inventions or improvements made within five (5)
years from the date hereof shall be primarily and significantly useful in the
Field, it shall so notify PerSeptive in writing and, PerSeptive shall be
precluded from selling, licensing or otherwise distributing any Tools (i) which
are Covered By patents or patent applications claiming or, (ii) incorporating,
manufactured using, based upon, using, arising out of or derived from, such
invention or improvement to any third party for a period of [*******]
following the date that the invention or improvement was made. If PerSeptive
shall object to such determination in writing within thirty (30) days after such
notice, the Parties shall negotiate in good faith to resolve whether such
invention or improvement is primarily and significantly useful in the Field and
if they cannot, the matter shall be referred to and determined by arbitration
in accordance with Section 15 hereof.

                           2.4.3. RESTRICTIONS ON LICENSING JOINT INVENTIONS.
Without the prior written consent of PerSeptive, ChemGenics shall not grant a
license or other right to any third party to develop, make, have made, use,
offer to sell, sell, import, license or otherwise distribute any Tools in the
PerSeptive Field Covered By, using, arising out of or derived from any invention
or improvement jointly owned by the Parties. Without the prior written consent
of ChemGenics, PerSeptive shall not grant a license or other right to any third
party to use or practice any invention or improvement jointly owned by the
Parties, or to develop, make, have made, use, offer to sell, sell, import or
otherwise distribute any products or deliver any services, in the Field Covered
By, using, arising out of or derived from any such joint invention or
improvement; provided, however, pursuant to Section 2.4.2 hereof, PerSeptive
shall have the right to grant restricted or unrestricted User Licenses and
provide and perform and permit others to perform pre- and post-sale services,
consistent with PerSeptive's current practice, to purchasers of or related to
Tools that may be Covered By, use, arise out of or be derived from any such
joint invention or improvement.

                           2.4.4. JOINT INVENTIONS WHICH ARE DRUGS. In the event
that any joint invention is a drug or drug candidate, PerSeptive hereby grants
to ChemGenics an exclusive, irrevocable, worldwide, royalty free, fully paid
right and license, terminable only as set forth in Section 9.3, to the Licensed
Technology to the extent necessary to further develop, and to make, have made,
use, offer to sell, sell and import such drug or drug candidate.
<PAGE>   6
                                      - 6 -



         3.       PAYMENT.

         The consideration delivered to PerSeptive on the Closing Date in
accordance with the Master Agreement, by ChemGenics (excluding the Earnout
Shares, as defined therein) shall constitute the consideration for PerSeptive's
entering into this Agreement. The Parties agree that no future performance is
required by PerSeptive during the term of this Agreement or otherwise in order
to earn the consideration described in this Section 3.

         4.       REPRESENTATIONS AND WARRANTIES.

                  4.1. REPRESENTATIONS, WARRANTIES AND COVENANTS OF PERSEPTIVE.
PerSeptive PTC-II and Vestec represent, warrant and covenant to ChemGenics as
follows:

                           4.1.1. Each of PerSeptive Biosystems, Inc., PTC-II
and Vestec is a corporation duly organized, validly existing and in good
standing under the laws of its state of incorporation with corporate powers
adequate for executing and delivering, and performing its obligations under,
this Agreement;

                           4.1.2. The execution, delivery and performance of
this Agreement have been duly authorized by all necessary corporate action on
the part of PerSeptive Biosystems, Inc., PTC-II and Vestec;

                           4.1.3. This Agreement has been duly executed and
delivered by PerSeptive and PTC-II and is a legal, valid and binding obligation
of each of PerSeptive Biosystems, Inc., PTC-II and Vestec, enforceable against
each of them in accordance with its terms;

                           4.1.4. The execution, delivery and performance of
this Agreement do not and will not conflict with or contravene any provision of
the charter documents or by-laws of PerSeptive Biosystems, Inc., PTC-II or
Vestec or any agreement, document, instrument, indenture or other obligation of
PerSeptive Biosystems, Inc., PTC-II or Vestec; and

                           4.1.5. Neither PerSeptive Biosystems, Inc., PTC-II
nor Vestec shall enter into any agreement, make any commitment, take any action
or fail to take any action that would contravene any material provision of, or
materially derogate or restrict any of the rights and licenses granted to
ChemGenics under, this Agreement.

                           4.1.6. PerSeptive shall grant ChemGenics reasonable
access to any prototype systems, instruments or other equipment (including any
reagents or media relating thereto) relevant to the Field, at such time as
PerSeptive shall reasonably deem access by third parties to such prototype is
appropriate, and subject to reasonable terms and conditions. In the event that
PerSeptive wishes to "beta test" any such system, instrument, equipment,
reagents or media on the premises of one or more of its customers, PerSeptive
shall give ChemGenics the opportunity, if ChemGenics so chooses, to be one of
the first such beta-test sites, subject to reasonable terms and conditions.
<PAGE>   7
                                      - 7 -



                           4.1.7. Schedule B sets forth a list of all patents
and patent applications currently owned or exclusively licensed by PerSeptive,
including all patents and patent applications used in the Drug Discovery Program
(as defined in the Master Agreement). To the best of PerSeptive's knowledge, all
patents listed in Schedule B are valid and in full force and all applications
listed therein as pending have been prosecuted in good faith as required by law
and are in good standing. To the best of PerSeptive's knowledge, there has been
no infringement by PerSeptive or its Affiliates with respect to any patent
rights of others in the conduct or operation of the Drug Discovery Program.
Except as disclosed in Schedule B, none of the patents or patent applications
listed or described in Schedule B is involved in any interference or opposition
proceeding, and there has been no written notice received by the Seller or any
of its affiliates or any other indication that any such proceeding will
hereafter be commenced. Also, included in Schedule B is a list of all exclusive
licenses and license agreements, and the patents and patent applications covered
thereby, relating to Licensed Technology that have been of significant use by
PerSeptive in the Drug Discovery Program during the two year period ending on
April 30, 1996. To the best of PerSeptive's knowledge, all of the licenses
listed or described in Schedule B are legally valid and binding and in full
force and effect. PerSeptive is not in default under any such license and, to
the best of PerSeptive's knowledge, there are no defaults by any other party to
any such license. None of PerSeptive's rights thereunder will be impaired by the
consummation of the transactions contemplated hereby. Except as described in
Schedule B, PerSeptive has not granted any person or entity any exclusive right
to use any of the patents or patent applications listed therein for any purpose.

                  4.2. REPRESENTATIONS, WARRANTIES AND COVENANTS OF CHEMGENICS.
ChemGenics represents, warrants and covenants to PerSeptive as follows:

                           4.2.1. ChemGenics is a corporation duly organized,
validly existing and in good standing under the laws of the State of Delaware
with corporate powers adequate for executing and delivering, and performing its
obligations under, this Agreement;

                           4.2.2. The execution, delivery and performance of
this Agreement have been duly authorized by all necessary corporate action on
the part of ChemGenics;

                           4.2.3. This Agreement has been duly executed and
delivered by ChemGenics and is a legal, valid and binding obligation of
ChemGenics, enforceable against ChemGenics in accordance with its terms;

                           4.2.4. The execution, delivery and performance of
this Agreement do not and will not conflict with or contravene any provision of
the charter documents or by-laws of ChemGenics or any agreement, document,
instrument, indenture or other obligation of ChemGenics; and

                           4.2.5. ChemGenics shall not enter into any agreement,
make any commitment, take any action or fail to take any action that would
contravene any material provisions of, or materially derogate or restrict any of
the rights and licenses granted to, PerSeptive under this Agreement.
<PAGE>   8
                                      - 8 -



         5.       DISCLOSURE OF LICENSED TECHNOLOGY.

                  5.1. DOCUMENTATION AND ACCESS. Upon request by ChemGenics from
time to time, PerSeptive shall, within a reasonable time thereafter, deliver to
ChemGenics copies of reasonable then-existing documentation describing the
Licensed Technology which is reasonably related to the scope of ChemGenics's
activities within the Field. PerSeptive shall give access to and use reasonable
efforts to keep ChemGenics apprised of all ongoing and future Licensed
Technology created by PerSeptive and its Affiliates which is or may be useful in
the Field, and shall reasonably cooperate with and provide advice to ChemGenics
with respect to the implementation of new Technology which is Licensed
Technology in the Field subject to the terms of this Agreement, it being
understood that the level of effort required by this Section is less than the
level of effort required by the Consulting and Interim Services Agreement (as
defined in the Master Agreement). PerSeptive further agrees, at the request of
ChemGenics, to provide reasonable additional consulting services to ChemGenics
in return for commercially reasonable compensation. PerSeptive shall at all
times during the term of this Agreement provide ChemGenics with access to
PerSeptive's patent applications and notify ChemGenics when any patents issue
thereon subject to Sections 9.2, 9.3 and 9.4 hereof. In the event the ChemGenics
shall have reason to believe that PerSeptive has not complied with the
requirements of this Section 5.1, it shall so notify PerSeptive and PerSeptive
shall be given a reasonable opportunity to cure such non-compliance.

                  5.2. PATENTS.

                           5.2.1. PATENT PROSECUTION. PerSeptive shall have the
exclusive right, at its expense, to prepare, prosecute and maintain patent
applications, and to maintain and enforce patents comprising the PerSeptive
Patent Rights and, except as expressly otherwise set forth herein, otherwise
deal in and with and enforce rights associated with the Licensed Technology. In
the event that PerSeptive elects not to prepare, prosecute or maintain any
patent application or any patent rights constituting PerSeptive Patent Rights,
PerSeptive shall promptly notify ChemGenics, and ChemGenics shall have the right
to prepare, prosecute and maintain any such application or right at ChemGenics's
expense.

                           5.2.2. COOPERATION. ChemGenics agrees to cause each
of its employees and agents to take all actions and to execute, acknowledge and
deliver all instruments or agreements reasonably requested by PerSeptive, and
necessary for the perfection, maintenance, enforcement or defense of that
PerSeptive's rights as set forth above.

                           5.2.3. IDENTIFICATION OF PATENT RIGHTS. ChemGenics
shall include in the packaging or documentation for any Products or Services, as
the case may be, adequate notice of the PerSeptive Patent Rights therein.

                  5.3. CONFIDENTIAL INFORMATION. Any Party receiving
Confidential Information shall use commercially reasonable efforts to: (i)
maintain the confidential and proprietary status of such Confidential
Information; (ii) keep such Confidential Information and each part thereof
within its possession or under its control sufficient to prevent any
<PAGE>   9
                                      - 9 -


activity with respect to the Confidential Information that is not specifically
authorized by this Agreement; (iii) prevent the disclosure of any Confidential
Information to any other Person; and (iv) ensure that such Confidential
Information is used only for those purposes specifically authorized herein;
provided, however, that such restriction shall not apply to any Confidential
Information which is (a) independently developed by the receiving Party without
reference to Confidential Information, (b) in the public domain at the time of
its receipt or thereafter becomes part of the public domain through no fault of
the receiving Party, (c) received without an obligation of confidentiality from
a third party having the right to disclose such information, (d) released from
the restrictions of this Section 5.3 by the express written consent of the
disclosing Party, (e) disclosed to any actual or prospective permitted Partner,
assignee, sublicensee or subcontractor of either PerSeptive or ChemGenics
hereunder or under the Master Agreement (if such actual or prospective Partner,
assignee, sublicense or subcontractor is subject to the provisions of this
Section 5.3 or comparable provisions of such other documents), or (f) required
by law, statute, rule or court order to be disclosed (the disclosing party
shall, however, use commercially reasonable efforts to obtain confidential
treatment of any such disclosure) and shall notify the other party in writing of
the request or requirement as soon as feasible so that such other party may make
timely effort to protect or limit the conditions of disclosure of its
Confidential Information. Notwithstanding clause (e), ChemGenics shall not have
the right to disclose Confidential Information of PerSeptive to a prospective
Partner, assignee, licensee or subcontractor which is a PerSeptive Competitor
unless and until such Person becomes an actual Partner, assignee, licensee or
subcontractor. Without limiting the generality of the foregoing, PerSeptive and
ChemGenics each shall use its commercially reasonable efforts to obtain
confidentiality agreements from its respective Partners, employees and agents,
similar in scope to this Section 5.3, to protect the Confidential Information,
including in the case of ChemGenics, commercially reasonable efforts to obtain
the agreement of Partners who are PerSeptive Competitors to not give access to
Confidential Information of PerSeptive to persons who are engaged in the
portions of the Partner's business which competes with the business of
PerSeptive in the PerSeptive Field. ChemGenics shall not use PerSeptive's
Confidential Information for any purpose outside the Field.

                  5.4. PERMITTED DISCLOSURES. Notwithstanding the provisions of
Section 5.3 hereof, PerSeptive and ChemGenics may, to the extent necessary,
disclose and use Confidential Information (other than Confidential Information
furnished to a Party by a third party or which a Party has an obligation to a
third party not to disclose), consistent with the rights of PerSeptive and
ChemGenics otherwise granted hereunder (a) for the purpose of securing
institutional or government approval to clinically test or market any Product,
or (b) for the purpose of securing patent protection for an invention within the
scope of the PerSeptive Patent Rights or any invention jointly owned by the
parties or owned solely by ChemGenics; provided, however, that in each such
instance (i) the other Party hereto shall have been notified of the permitted
disclosure and (ii) except in the case of disclosures to government entities in
which the party makes commercially reasonable efforts to protect the
confidentiality thereof to the extent permitted by applicable law, any such
disclosure shall be made to Persons which either have agreed to be bound by or
are already subject to a duty of confidentiality, for the benefit of a Party
hereto, substantially to the same effect as that set forth in Section 5.3
hereof.
<PAGE>   10
                                     - 10 -


         6.       INFRINGEMENT.

                  6.1. NOTIFICATION OF INFRINGEMENT. ChemGenics shall notify
PerSeptive of any infringement or misappropriation known to ChemGenics by any
Person of any Licensed Technology rights and shall provide PerSeptive with the
available evidence, if any, of such infringement. If ChemGenics has actual
notice of infringement by any Person of Licensed Technology rights, the
respective officers of PerSeptive and ChemGenics shall confer to determine in
good faith an appropriate course of action to enforce the Licensed Technology
rights or otherwise abate the infringement thereof. All amounts recovered in any
action to enforce Licensed Technology rights undertaken by PerSeptive and
ChemGenics, whether by judgment or settlement, shall be retained by PerSeptive
and ChemGenics pro rata according to the respective percentages of expenses
borne by them in enforcing such rights.

                  6.2. ENFORCEMENT OF LICENSED TECHNOLOGY RIGHTS. If PerSeptive
determines that enforcement of the Licensed Technology rights is appropriate,
PerSeptive shall have the right, but not the obligation, at its own expense, to
take appropriate action to enforce such rights; provided, however, that, if
PerSeptive elects to so act, ChemGenics shall have the right to participate in
the enforcement of such rights by agreeing to bear a percentage of the costs of
such enforcement in such amount as the parties shall determine. All amounts
recovered in any action to enforce Licensed Technology rights undertaken by
ChemGenics and PerSeptive, whether by judgment or settlement, shall be retained
by ChemGenics and PerSeptive pro rata according to the respective percentages of
expenses borne by them in enforcing such Licensed Technology rights. If, within
six (6) months after notice of infringement, PerSeptive has not commenced action
to enforce such rights or thereafter ceases to diligently pursue such action,
ChemGenics shall have the right, at its expense, to take appropriate action to
enforce such rights as its sole remedy hereunder. All amounts recovered in any
action to enforce Licensed Technology rights undertaken by ChemGenics solely at
its expense, whether by judgment or settlement, shall be retained by ChemGenics.
PerSeptive and ChemGenics shall fully cooperate with each other in the planning
and execution of any action to enforce rights. Neither PerSeptive nor ChemGenics
shall enter into any settlement that includes the grant of a license under,
agreement not to enforce, or any statement prejudicial to the validity or
enforceability of any Licensed Technology rights without the consent of the
other, which consent shall not be unreasonably withheld or delayed.

                  6.3. DISCLAIMER OF WARRANTY; CONSEQUENTIAL DAMAGES.

                           6.3.1. Reference is made to certain representations
made by PerSeptive in Section 4.1 hereof concerning its intellectual property
rights. Nothing in this Agreement shall be construed as a representation made or
warranty given by PerSeptive that any patents will issue based on pending
applications within the PerSeptive Patent Rights, or that any such patents which
do issue will be valid. Except for the express representations and warranties
set forth herein, PERSEPTIVE EXPRESSLY DISCLAIMS AND CHEMGENICS HEREBY WAIVES,
RELEASES AND RENOUNCES ANY WARRANTY, EXPRESS OR IMPLIED, WITH RESPECT TO THE
LICENSED TECHNOLOGY, INCLUDING,
<PAGE>   11
                                     - 11 -



WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE.

                           6.3.2. NEITHER PARTY TO THIS AGREEMENT SHALL BE
ENTITLED TO RECOVER FROM THE OTHER ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL,
MULTIPLE OR PUNITIVE DAMAGES.

         7.       CHEMGENICS' RIGHT TO INDEMNIFICATION.

         PerSeptive shall indemnify the ChemGenics Indemnitees, pay on demand
and protect, defend, save and hold harmless each ChemGenics Indemnitee from and
against, on an after-tax basis, any and all Claims incurred by or asserted
against any ChemGenics Indemnitee of whatever kind or nature, including, without
limitation, any claim or liability based upon negligence, warranty, strict
liability, violation of government regulation or infringement of patent or other
proprietary rights, arising from or occurring as a result of (a) the use of the
Licensed Technology by PerSeptive or any Affiliate, agent or sublicensee of
PerSeptive (other than ChemGenics) or (b) subject to Section 6.3.2, any breach
of this Agreement by PerSeptive, except to the extent that any Claims shall have
arisen from the negligence or willful misconduct of any ChemGenics Indemnitee.
Such ChemGenics Indemnitee shall promptly notify PerSeptive of any Claim with
respect to which such ChemGenics Indemnitee is seeking indemnification
hereunder, upon becoming aware thereof, and permit PerSeptive at PerSeptive's
cost to defend against such Claim and shall cooperate in the defense thereof.
Neither PerSeptive nor such ChemGenics Indemnitee shall enter into, or permit,
any settlement of any such Claim without the express written consent of the
other Party which consent shall not be unreasonably withheld or delayed. Such
ChemGenics Indemnitee may, at its option and expense, have its own counsel
participate in any proceeding which is under the direction of PerSeptive and
will cooperate with PerSeptive or its insurer in the disposition of any such
matter; provided, however, that if PerSeptive shall not defend such Claim, such
ChemGenics Indemnitee shall have the right to defend such Claim itself and
recover from PerSeptive all reasonable attorneys' fees and expenses incurred by
it during the course of such defense.

         8.       PERSEPTIVE RIGHT TO INDEMNIFICATION.

         ChemGenics shall indemnify the PerSeptive Indemnitees, pay on demand
and protect, defend, save and hold harmless each PerSeptive Indemnitee from and
against, on an after-tax basis, any and all Claims incurred by or asserted
against any PerSeptive Indemnitee of whatever kind or nature, including, without
limitation, any claim or liability based upon negligence, warranty, strict
liability, violation of government regulation or infringement of patent or other
proprietary rights, arising from or occurring as a result of (a) the use of any
Licensed Technology by ChemGenics or any permitted sublicensee of ChemGenics
(other than PerSeptive) or (b) subject to Section 6.3.2, any breach of this
Agreement by ChemGenics, except to the extent that any Claims shall have arisen
from the negligence or willful misconduct of any PerSeptive Indemnitee. Such
PerSeptive Indemnitee shall promptly notify ChemGenics of any Claim with respect
to which such PerSeptive Indemnitee is seeking indemnification hereunder, upon
becoming aware thereof, and permit ChemGenics at
<PAGE>   12
                                     - 12 -



ChemGenics's cost to defend against such Claim and shall cooperate in the
defense thereof, provided, however, that PerSeptive shall have the right, but
not the obligation, to control the defense, at its expense, of any such Claims
involving PerSeptive Patent Rights. Neither such PerSeptive Indemnitee nor
ChemGenics shall enter into, or permit, any settlement of any such Claim without
the express written consent of the other Party, which shall not unreasonably be
withheld or delayed. Such PerSeptive Indemnitee may, at its option and expense,
have its own counsel participate in any proceeding which is under direction of
ChemGenics and will cooperate with ChemGenics and its insurer in the disposition
of any such matter; provided, however, that if ChemGenics shall not defend such
Claim, such PerSeptive Indemnitee shall have the right to defend such Claim
itself and recover from ChemGenics all reasonable attorneys' fees and expenses
incurred by it during the course of such defense.

         9.       TERM AND TERMINATION.

                  9.1. TERM. This Agreement shall be effective as of the Closing
Date and shall continue in full force and effect indefinitely, unless terminated
in part as provided in Sections 9.2, 9.3 or 9.4 hereof.

                  9.2. TERMINATION UPON BANKRUPTCY, ETC.. Either Party shall
have the right to terminate this Agreement (except for the license granted by
Section 2.1.1(b)), effective immediately upon written notice of termination to
the other Party in the event that:

                           9.2.1. The other Party shall (i) seek the
liquidation, reorganization, dissolution or winding-up of itself or the
composition or readjustment of its debts, (ii) apply for or consent to the
appointment of, or the taking of possession by, a receiver, custodian, trustee
or liquidator of itself or of all or a substantial part of its assets, (iii)
make a general assignment for the benefit of its creditors, (iv) commence a
voluntary case under the federal Bankruptcy Code, (v) file a petition seeking to
take advantage of any other law relating to bankruptcy, insolvency,
reorganization, winding-up or composition or readjustment of debts, or (vi)
adopt any resolution of its Board of Directors or stockholders for the purpose
of effecting any of the foregoing; or

                           9.2.2. A proceeding or case shall be commenced
without the application or consent of the other Party and such proceeding or
case shall continue undismissed, or an order, judgment or decree approving or
ordering any of the following shall be entered and continue unstayed and in
effect, for a period of forty-five (45) days from and after the date service of
process is effected upon the other Party, seeking (i) the other Party's
liquidation, reorganization, dissolution or winding-up, or the composition or
readjustment of its debts, (ii) the appointment of a trustee, receiver,
custodian, liquidator or the like of the other Party or of all or any
substantial part of its assets, or (iii) similar relief in respect of the other
Party under any law relating to bankruptcy, insolvency, reorganization,
winding-up or the composition or readjustment of debts.
<PAGE>   13
                                     - 13 -


                  9.3 TERMINATION OF MASTER AGREEMENT. If the Master Agreement
shall terminate or the transactions contemplated therein are rescinded or
unwound for any reason, all licenses granted under Section 2.1 hereof and the
obligations of PerSeptive under Sections 4.1.6, 5.1, 6.1, 6.2 and 14 hereof
shall terminate and all other provisions of the Agreement shall survive,
provided, however, that, to the extent that a continuing license shall be
necessary for ChemGenics to practice, exploit or commercialize any invention
made by ChemGenics prior to the rescission of the Master Agreement, then (i) if
the invention is a drug or drug candidate or drug target, PerSeptive shall grant
to ChemGenics a worldwide non-exclusive, perpetual, royalty-free license under
the Licensed Technology to the extent necessary to make, use or sell such drug,
drug candidate or drug target and (ii) if the invention is not a drug, drug
candidate or drug target, (a) if such continuing license is no broader than a
User License that PerSeptive makes generally available to its customers,
PerSeptive will provide such User License by ChemGenics from PerSeptive on terms
no less favorable than those offered to its other customers and (b) if
ChemGenics requires a broader license than is currently available in connection
with the purchase of products under any User License then PerSeptive shall grant
an additional worldwide, non-exclusive, perpetual, royalty-free license under
the Licensed Technology solely to the extent necessary for ChemGenics to
practice, exploit and commercialize such invention in the Field; provided that
ChemGenics shall purchase the PerSeptive products necessary to obtain such User
License. In addition, in the event the Master Agreement shall terminate or the
transactions contemplated therein are rescinded or unwound for any reason,
ChemGenics shall grant to PerSeptive a worldwide, non-exclusive, perpetual,
royalty-free license in the PerSeptive Field to any improvement to the Licensed
Technology made by ChemGenics between the date hereof and the date of such
rescission.

                  9.4 ACQUISITION OF CHEMGENICS BY PERSEPTIVE COMPETITOR. In the
event that ChemGenics shall consolidate or merge with another Person that is a
PerSeptive Competitor, or convey, sell or lease to a PerSeptive Competitor all
or substantially all of the stock, assets or business of ChemGenics and its
subsidiaries, taken as a whole, or suffer a Change of Control in which a
PerSeptive Competitor shall come to control ChemGenics, then PerSeptive may, in
its sole discretion within twenty (20) days after receipt of the notice required
by Section 14 hereof, give notice that it will terminate all licenses granted
under Section 2.1 (except Section 2.1.1(b)) hereof and the obligations of
PerSeptive under Sections 4.1.6, 5.1, 6.1, 6.2, 13 and 14 hereof effective on
the closing of the relevant transaction, and upon such closing all such licenses
and obligations under Sections 2.1 (except Section 2.1.1(b)), 4.1.6, 5.1, 6.1,
6.2, 13 and 14 hereof shall terminate, provided, however, that all other
provisions of this Agreement shall survive.

                  9.5 INDEMNIFICATION. Notwithstanding the foregoing, the
indemnification provisions of Section 8 hereof shall survive termination or
expiration of this Agreement, but only with respect to Claims which arose from
acts or circumstances which occurred prior to termination.
<PAGE>   14
                                     - 14 -



         10.      NO IMPLIED WAIVERS; RIGHTS CUMULATIVE.

         No failure on the part of PerSeptive or ChemGenics to exercise and no
delay in exercising any right, power, remedy or privilege under this Agreement,
or provided by statute or at law or in equity or otherwise, including, without
limitation, the right or power to terminate this Agreement, shall impair,
prejudice or constitute a waiver of any such right, power, remedy or privilege
or be construed as a waiver of any breach of this Agreement or as an
acquiescence therein, nor shall any single or partial exercise of any such
right, power, remedy or privilege preclude any other or further exercise thereof
or the exercise of any other right, power, remedy or privilege.

         11.      FORCE MAJEURE.

         PerSeptive and ChemGenics shall each be excused for any failure or
delay in performing any of its respective obligations under this Agreement,
other than the obligations of ChemGenics to make certain payments to PerSeptive
as described in Section 3 hereof, if such failure or delay is caused by Force
Majeure.

         12.      NOTICES.

         All notices, requests and other communications to PerSeptive or
ChemGenics hereunder shall be in writing (including telecopy or similar
electronic transmissions), shall refer specifically to this Agreement and shall
be personally delivered or sent by telecopy or other electronic facsimile
transmission, by registered mail or certified mail, return receipt requested,
postage prepaid or by reliable overnight courier service providing evidence of
receipt, in each case to the respective address specified below (or to such
address as may be specified in writing to the other party hereto):

              PerSeptive Biosystems, Inc.
              500 Old Connecticut Path
              Framingham, MA 01701
              Attn:  President
              Facsimile: (508) 383-7852

              With a copy to:

              Rufus C. King, Esq.
              Testa, Hurwitz & Thibeault, LLP
              125 High Street
              High Street Tower
              Boston, MA  02110
              Facsimile:  (617) 248-7100
<PAGE>   15
                                     - 15 -



              ChemGenics Pharmaceuticals Inc.
              One Kendall Square
              Building 300
              Cambridge, MA  02139
              Attn: President
              Facsimile: (617) 225-2997

              With a copy to:

              Jeffrey M. Wiesen, Esq.
              Mintz, Levin, Cohn, Ferris,
                  Glovsky and Popeo, P.C.
              One Financial Center
              Boston, MA  02111
              Facsimile:  (617) 542-2241

Any notice or communication given in conformity with this Section 12 shall be
deemed to be effective: (i) when received by the addressee, if delivered by hand
or electronic facsimile; (ii) three (3) days after mailing, if mailed; and (iii)
one (1) business day after delivery to a reliable overnight courier service
providing evidence of receipt.

         13.      FURTHER ASSURANCES.

         Each of PerSeptive and ChemGenics agrees to duly execute and deliver,
or cause to be duly executed and delivered, such further instruments and to do
and cause to be done such further acts and things, that may be necessary or as
the other Party hereto may at any time and from time to time reasonably request
to carry out more effectively the provisions, or to better assure and confirm
unto such other Party, its rights under this Agreement.

         14.      SUCCESSORS AND ASSIGNS.

         The terms and provisions of this Agreement shall inure to the benefit
of, and be binding upon, PerSeptive, ChemGenics, and their respective successors
and assigns, subject to the terms of Section 9.4 hereof and the remainder of
this Section 14; provided, however, that ChemGenics may not assign or otherwise
transfer this Agreement or any of its rights and interests, nor delegate any of
its obligations, hereunder, except to a direct or indirect 100% parent or direct
or indirect wholly owned subsidiary which becomes a party to the Non-Competition
Agreement (as defined in the Master Agreement) and that agrees in writing to be
bound by this Agreement (and in such case ChemGenics shall remain bound) without
the prior written consent of PerSeptive, except pursuant to a merger or
consolidation, or sale of all or substantially all of the stock, assets or
business of ChemGenics and its subsidiaries taken as a whole as provided below.
In the event that either Party shall consolidate or merge with another Person
(other than an acquisition by such Party of another Person where the
stockholders of such Party (or any subsidiary thereof) after such transaction
directly or indirectly own at least a majority of the voting stock of the
combined or acquired Person); or convey, sell or lease to another Person all or
substantially all of the stock, assets or business
<PAGE>   16
                                     - 16 -



of such Party and its subsidiaries, taken as a whole, or if there shall be a
Change of Control of such Party, then (i) if such transaction is negotiated by
such Party, such Party shall give the other Party written notice identifying the
acquiring Person and the material terms of the transaction at least thirty (30)
days prior to the closing thereof and (ii) the Parties shall negotiate in good
faith to determine whether any changes shall be appropriate in this Agreement
and/or in the consideration due to PerSeptive for the licenses granted herein as
a result of the proposed transaction and the changed relationship of the Parties
resulting therefrom, subject to PerSeptive's right to terminate the licenses
granted herein pursuant to Section 9.4 hereof. If the Parties are unable to
agree that any such changes should be made prior to the closing of the proposed
transaction, then the licenses granted herein shall continue unaffected thereby
upon the consummation of the transaction, subject to PerSeptive's right to
terminate such licenses pursuant to Section 9.4. Any attempt to assign or
delegate any portion of this Agreement in violation of this Section 14 shall be
null and void. Subject to the foregoing, any reference to PerSeptive and
ChemGenics hereunder shall be deemed to include the permitted successors thereto
and assigns thereof.

         15.      AMENDMENTS.

         No amendment, modification, waiver, termination or discharge of any
provision of this Agreement, nor any consent to any departure by PerSeptive or
ChemGenics therefrom, shall in any event be effective unless the same shall be
in writing specifically identifying this Agreement and the provision intended to
be amended, modified, waived, terminated or discharged and signed by PerSeptive
and ChemGenics, and each such amendment, modification, waiver, termination or
discharge shall be effective only in the specific instance and for the specific
purpose for which given. No provision of this Agreement shall be varied,
contradicted or explained by any oral agreement, course of dealing or
performance or any other matter not set forth in an agreement in writing and
signed by PerSeptive and ChemGenics.

         16.      ARBITRATION

         (a) The Parties shall attempt to resolve any dispute or controversy
arising under or relating to the interpretation or meaning of this Agreement by
good faith negotiations. Any matter that cannot be resolved by such good faith
negotiation shall be resolved by final and binding arbitration conducted by
three (3) arbitrators in Boston, Massachusetts, in accordance with the
then-current American Arbitration Association ("AAA") Commercial Arbitration
Rules (the "AAA Rules") as modified by this Section 16.

         (b) The arbitrators shall be selected by mutual agreement of the
parties or, failing such agreement, in accordance with the aforesaid AAA Rules.
At least one (1) of the arbitration panel shall be reasonably familiar with the
biotechnology industry. The Parties shall bear the costs of the arbitrators
equally. No arbitrator may be affiliated in any way with either Party.
<PAGE>   17
                                     - 17 -



         (c) The Parties shall have the right of limited pre-hearing discovery,
in accordance with the U.S. Federal Rules of Civil Procedure, as then in effect,
for a period not to exceed sixty (60) days.

         (d) As soon as the discovery is concluded, but in any event with thirty
(30) days thereafter, the arbitrators shall hold a hearing in accordance with
the AAA Rules. Thereafter, the arbitrators shall promptly render a written
decision, together with a written opinion setting forth in reasonable detail the
grounds for such a decision.

         (e) Judgment may be entered in any court of competent jurisdiction to
enforce the award entered by the arbitrators.

         (f) The duty of the Parties to arbitrate any dispute hereunder shall
survive expiration or termination of this Agreement for any reason.

         17.      GOVERNING LAW.

         This Agreement shall be governed by and construed in accordance with
the laws of the Commonwealth of Massachusetts.

         18.      SEVERABILITY.

         If any provision hereof should be held invalid, illegal or
unenforceable in any respect in any jurisdiction, then, to the fullest extent
permitted by law, (a) all other provisions hereof shall remain in full force and
effect in such jurisdiction and shall be liberally construed in order to carry
out the intentions of the parties hereto as nearly as may be possible and (b)
such invalidity, illegality or unenforceability shall not affect the validity,
legality or enforceability of such provision in any other jurisdiction. To the
extent permitted by applicable law, PerSeptive and ChemGenics hereby waive any
provision of law that would render any provision hereof prohibited or
unenforceable in any respect.

         19.      HEADINGS.

         Headings used herein are for convenience only and shall not in any way
affect the construction of, or be taken into consideration in interpreting, this
Agreement.

         20.      EXECUTION IN COUNTERPARTS.

         This Agreement may be executed in any number of counterparts, each of
which counterparts, when so executed and delivered, shall be deemed to be an
original, and all of which counterparts, taken together, shall constitute one
and the same instrument.

         21.      ENTIRE AGREEMENT.
<PAGE>   18
                                     - 18 -


         This Agreement, together with any agreements referenced herein,
constitutes, on and as of the date hereof, the entire agreement of PerSeptive
and ChemGenics with respect to the subject matter hereof, and all prior or
contemporaneous understandings or agreements, whether written or oral, between
PerSeptive and ChemGenics with respect to such subject matter are hereby
superseded in their entirety.

         IN WITNESS WHEREOF, the parties hereto have caused this License
Agreement to be duly executed under seal and delivered as of the date first
above written.


                                        PERSEPTIVE BIOSYSTEMS, INC.


                                        By:_____________________________________

                                        Title:__________________________________


                                        PERSEPTIVE TECHNOLOGIES II
                                        CORPORATION


                                        By:_____________________________________

                                        Title:__________________________________


                                        VESTEC CORPORATION


                                        By:_____________________________________

                                        Title:__________________________________


                                        CHEMGENICS PHARMACEUTICALS INC.


                                        By:_____________________________________

                                        Title:__________________________________
<PAGE>   19
                                LICENSE AGREEMENT

                                   SCHEDULE A

                                   DEFINITIONS


         "AFFILIATE" of a Person shall mean a Person that directly, or
indirectly through one or more intermediaries, controls, is controlled by or is
under common control with such Person. "Control" (and, with correlative
meanings, the terms "controlled by" and "under common control with") shall mean
the possession of the power to direct or cause the direction of the management
and policies of such Person, whether through the ownership of voting stock, by
contract or otherwise. In the case of a corporation, "control" shall mean, among
other things, the direct or indirect ownership of more than fifty percent (50%)
of its outstanding voting stock. Notwithstanding the forgoing, ChemGenics and
PerSeptive shall not be deemed to be Affiliates for the purpose of this
Agreement.

         "ASSOCIATED TECHNOLOGY" shall mean all Technology (including, without
limitation, Technology licensed to PerSeptive, subject to Section 2.1.3 hereof)
relating to or useful in the Field, other than PerSeptive Patent Rights, (i)
owned or controlled by or licensed to, PerSeptive as of the date hereof, or
acquired by PerSeptive hereafter that relates to and is useful in researching,
developing or manufacturing Products or in the delivery of Services. "Owned or
controlled" shall include Technology which PerSeptive owns, or under which
PerSeptive is licensed and has the right to grant sublicenses and/or grant
immunity from suit.

         "CHANGE IN CONTROL" means with respect to either Party any transaction
or any event as a result of which any one or more Persons (other than a
stockholder of the Party on the Closing Date) acquires or for the first time
controls or is able to vote (directly or through nominees or beneficial
ownership) after the Closing Date fifty percent (50%) or more of the capital
stock of the Company outstanding at the time having power ordinarily to vote for
directors of the Company.

         "CHEMGENICS" shall mean ChemGenics Pharmaceuticals Inc., a Delaware
corporation.

         "CHEMGENICS INDEMNITEE" shall mean ChemGenics, its successors and
assigns, and the directors, officers, employees, agents and counsel thereof.

         "CLAIM" shall mean any and all liabilities, damages, losses,
settlements, claims, actions, suits, penalties, fines, costs or expenses
(including, without limitation, reasonable attorneys' fees).

         "CLOSING DATE" shall mean _____ __, 1996.



                                       A-1
<PAGE>   20
         "CONFIDENTIAL INFORMATION" shall mean all proprietary confidential
Technology owned or controlled by PerSeptive or ChemGenics, respectively, and
disclosed by PerSeptive to ChemGenics or by ChemGenics to PerSeptive during the
term of this Agreement.

         "COVERED BY" shall mean, with respect to any act, an act that would, in
the absence of a license provided hereunder, constitute an infringement of a
claim of a pending patent application, if issued as a patent, or a patent which
has not been held invalid or unenforceable by a court of competent jurisdiction
in a decision which is unappealable or the appeal period for which has expired
without an appeal being taken.

         "DRUG DISCOVERY PROGRAM" shall have the meaning assigned to that term
in the recitals to the Master Agreement.

         "FIELD" shall mean all applications of the Licensed Technology for (i)
drug discovery and (ii) the development, synthesis and manufacture of drugs and
drug candidates discovered by ChemGenics or its Partners.

         "FORCE MAJEURE" shall mean any act of God, any accident, explosion,
fire, storm, earthquake, flood, drought, peril of the sea, riot, embargo, war or
foreign, federal, state or municipal order of general application, seizure,
requisition or allocation, any failure or delay of transportation, shortage of
or inability to obtain supplies, equipment, fuel or labor or any other
circumstances or event beyond the reasonable control of the party relying upon
such circumstance or event.

         "LICENSED TECHNOLOGY" shall mean, collectively, the PerSeptive Patent
Rights and the Associated Technology.

         "PARTIES" means PerSeptive and ChemGenics.

         "PARTNER" shall mean any Person with whom ChemGenics shall have a
written research and/or development agreement or other collaborative arrangement
whereby ChemGenics receives either (i) ownership rights or license rights in
products of such research and/or development or (ii) royalty payments based on
the sales of such products.

         "PARTY" means PerSeptive or ChemGenics.

         "PERSEPTIVE" shall mean, unless the context otherwise requires,
PerSeptive Biosystems, Inc., a Delaware corporation, PTC-II and Vestec,
collectively.

         "PERSEPTIVE COMPETITOR" shall mean the Persons listed in Schedule C
hereto. PerSeptive may modify or supplement Schedule C from time to time to add
Persons who materially compete with PerSeptive in the PerSeptive Field and shall
modify Schedule C to delete Persons who do not materially compete with
PerSeptive in the PerSeptive Field, subject to ChemGenics' right to reasonably
object to any such modification or supplement or failure to modify Schedule C.
If ChemGenics does not object in writing to such modification or supplement
within twenty (20) days after receipt in writing of a modified or supplemented

                                       A-2
<PAGE>   21
schedule, or if ChemGenics shall object and the Parties are able to resolve such
objection after good faith negotiation within five days after PerSeptive's
receipt of such written objection, then such modification or supplement shall
become part of this Agreement. If the Parties are unable to resolve such
objection, the matter shall be referred to arbitration in accordance with
Section 16, provided that if the list is modified or supplemented the date of
such modification or supplement shall be the date the original modified or
supplemented list was first delivered to ChemGenics.

         "PERSEPTIVE FIELD" shall mean the research, development, design,
manufacture, importation, marketing, sales, licensing and distribution of Tools
and providing Tools to the life science industry.

         "PERSEPTIVE INDEMNITEE" shall mean PerSeptive, its successors and
assigns, and the directors, officers, employees, agents and counsel thereof.

         "PERSEPTIVE PATENT RIGHTS" shall mean rights (including, without
limitation, rights as licensee) now owned or hereafter acquired, subject to
Section 2.1.3 hereof, by PerSeptive under (i) issued U.S. and foreign patents,
(ii) U.S. or foreign patent applications, including any patent application
constituting an equivalent, counterpart, reissue, extension or continuation of
any of the foregoing applications (including, without limitation, a continuation
in part or division), or (iii) any patent issued or issuing upon any of the
foregoing applications. A list of PerSeptive's issued patents and patent
applications as of the date of this Agreement is attached hereto as Schedule B.

         "PERSEPTIVE USER LICENSE" shall mean a license or right to use or
practice the Licensed Technology that is granted or conveyed in connection with
the sale, license or other transfer of PerSeptive's products.

         "PERSON" shall mean any individual, partnership, limited liability
company, corporation, firm, association, unincorporated organization, joint
venture, trust or other entity.

         "PRODUCTS" shall mean a product or system developed by incorporating,
utilizing, manufactured using, based upon, arising out of, or derived from the
Licensed Technology.

         "PTC-II" shall mean PerSeptive Technologies II Corporation, a Delaware
corporation, and a wholly owned subsidiary of PerSeptive Biosystems, Inc.

         "SERVICES" shall mean a method, process or procedure incorporating,
utilizing, based upon, arising out of or derived from the Licensed Technology.

         "TECHNOLOGY" shall mean public and nonpublic technical or other
information, trade secrets, know-how, processes, formulations, concepts, ideas,
preclinical, clinical, pharmacological or other data and testing results,
experimental methods, or results, assays, descriptions, business or scientific
plans, depictions, customer lists and any other written, printed or
electronically stored materials, any natural or man-made biological materials
and

                                       A-3
<PAGE>   22
any and all other intellectual property, including licenses, patents and patent
applications, of any nature whatsoever.

         "TOOLS" shall mean instruments, equipment, machinery, apparatus,
devices, media, reagents, compounds, resins, activators, linkers, particles,
supports and other materials and substances (including, without limitation,
oligomers, peptides and other molecules), tools or other products (and systems
comprising the foregoing) for biomolecular purification, diagnosis, synthesis,
sequencing or analysis.

         "VESTEC" shall mean Vestec Corporation, a Texas corporation, and a
wholly owned subsidiary of PerSeptive Biosystems, Inc.




                                       A-4
<PAGE>   23

             Confidential Materials omitted and filed separately
                 with the Securities and Exchange Commission.
                       Asterisks denote such omissions.


                                   SCHEDULE B

                                  CONFIDENTIAL
                           PERSEPTIVE BIOSYSTEMS, INC.
                          ISSUED U.S. & FOREIGN PATENTS


                        Pages B-1 through B-7 contain
                      confidential materials which have
                      been omitted and filed separately
                 with the Securities and Exchange Commission.



                                       B-1


<PAGE>   24

             Confidential Materials omitted and filed separately
                 with the Securities and Exchange Commission.
                       Asterisks denote such omissions.


                                                                          Page 1
                                                                    CONFIDENTIAL
                                                                 Attorney-Client
                                                          Privileged Information



                           PERSEPTIVE BIOSYSTEMS, INC.
                           ---------------------------

                           Pending Patent Applications



                        Pages B2-1 through B-2 contain
                  Contain confidential materials which have
                      been omitted and filed separately
                 with the Securities and Exchange Commission.



<PAGE>   25



                                LICENSE AGREEMENT

                                   SCHEDULE C

                             PERSEPTIVE COMPETITORS



                                  Perkin Elmer
                                 Hewlett Packard
                                     Waters
                                     Beckman
                                     Bio Rad
                                    E. Merck
                                    Shimadzu
                                     Hitachi
                                 Thermo Electron
                               Pharmacia & Upjohn
                                    Amersham
                                      Tosoh
                                    Sepracor
                                   W.R. Grace


            and all Persons meeting the definition of an Affiliate of
     any of the foregoing if the 50% standard therein were changed to 20%.


                                       B-8


<PAGE>   26
             Confidential Materials omitted and filed separately
                 with the Securities and Exchange Commission.
                       Asterisks denote such omissions.



                      Confidential, Proprietary Information

                                    EXHIBIT D

                                       to
                                License Agreement
                                     between
                           PerSeptive Biosystems, Inc.
                                       and
                        ChemGenics Pharmaceuticals, Inc.
                        --------------------------------

                    Drug Discovery Program Research Projects.

   Identification of patents or patent applications which, in the opinion of
  PerSeptive's management, are particularly relevant to the Project (excluding
   patents or patent applications relating to instruments and other Tools (as
                       defined in the License Agreement)
                                       and

   Potential Drugs, Drug Targets and Drug Candidate Which are Subjects of Drug
                      Discovery Program Research Projects

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

[Key:  "No D.T.C." means No Potential Drugs, Drug Targets or Drug Candidates]


                        Pages D-1 through D-2 contain
                    confidential materials which have been
                         omitted and filed separately
                 with the Securities and Exchange Commission