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                                                                   EXHIBIT 10.48

                  CONFIDENTIALITY AND NON-COMPETITION AGREEMENT


         THIS CONFIDENTIALITY AND NON-COMPETITION AGREEMENT (this "Agreement")
is made and entered into as of the 28th day of June, 1996 by and between
ChemGenics Pharmaceuticals Inc., a Delaware corporation ("ChemGenics"), and
PerSeptive Biosystems, Inc., a Delaware corporation ("PBIO"). Capitalized terms
not defined herein shall have the meaning ascribed to them in the Master
Agreement (as hereinafter defined).

         WHEREAS, ChemGenics and PBIO have entered into a Master Agreement dated
as of May 7, 1996 (the "Master Agreement"), which provides for the sale, license
or transfer by PBIO to ChemGenics of certain of PBIO's assets, projects and
activities principally related to drug discovery activities and efforts
(collectively, the "Drug Discovery Program");

         WHEREAS, ChemGenics and PBIO have entered into a License Agreement of
even date (the "License Agreement"), which provides for the license by PBIO to
ChemGenics of certain PBIO technology for drug discovery purposes;

         WHEREAS, one of the conditions precedent to the consummation by the
parties of the transactions contemplated by the Master Agreement is that the
parties shall have entered into this Agreement.

         NOW THEREFORE, in consideration of the preceding recitals, the
covenants, conditions and agreements contained herein, and for other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the parties, intending to be legally bound, hereby agree as
follows:

         1.       PBIO Non-Competition Covenants.

                  (a) PBIO hereby covenants and agrees that, as long as the
License Agreement remains in effect, and except as otherwise provided in the
License Agreement or in that certain Consulting and Interim Services Agreement
of even date herewith between PBIO and ChemGenics (the "Consulting Agreement"),
neither PBIO nor any of its affiliates (other than ChemGenics) shall:

                  (i) engage in drug discovery or enter into any research and/or
         development agreement or other collaborative arrangement with a third
         party anywhere in the world for drug discovery whereby PBIO receives
         either (i) ownership rights or license rights in products of such
         research and/or development or collaborative arrangement, (ii) royalty
         payments based on sales of the products of such research and/or
         development or collaborative arrangement or (iii) cash or other
         compensation as fees or milestone payments based on the conduct or
         success of research efforts under such agreement or
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         arrangement, provided that the foregoing shall not be deemed to prevent
         PBIO from providing and performing, and permitting others to provide
         and perform, pre-sale and post-sale services consistent with PBIO's
         current practice related to products developed, made, manufactured,
         offered for sale, sold or distributed by PBIO; or

                  (ii) for themselves or on behalf of or through any third
         party, directly or indirectly, solicit, entice or persuade or attempt
         to solicit, entice or persuade any employees of or consultants to
         ChemGenics or its affiliates to terminate his or her employment with,
         consultancy to, or otherwise cease his or her relationship with
         ChemGenics or its affiliates for any reason.

                  (b) Reasonableness of Restrictions. PBIO recognizes and agrees
that the specific but broad geographical scope of the foregoing provisions is
reasonable, legitimate and fair in view of ChemGenics' present strategy and its
future needs to market its products in a large geographic area in order to have
a sufficient customer base to make ChemGenics' business profitable, and in view
of the consideration received by PBIO pursuant to the Master Agreement.

         2.       ChemGenics Non-Competition Covenants.

                  (a) ChemGenics hereby covenants and agrees that, as long as
the License Agreement remains in effect, and except as otherwise provided in the
License Agreement or Consulting Agreement, neither ChemGenics nor any of its
affiliates (other than PBIO) shall:

                  (i) offer to sell, sell or distribute anywhere in the world,
         except to Partners (as defined in the License Agreement) in connection
         with and pursuant to an agreement principally for drug discovery
         between ChemGenics and the Partner, any instruments, equipment,
         machinery, apparatus, devices, media, reagents, compounds, resins,
         activators, linkers, particles, supports or other materials or
         substances (including without limitation oligomers, peptides and other
         molecules), tools or other products or systems comprising the foregoing
         for the purification, analysis, sequencing or synthesis of molecules;
         provided that the foregoing shall not be construed to override the
         prohibition in Section 2.1.1 of the License Agreement against utilizing
         the Licensed Technology (as defined therein) to offer to sell, sell or
         distribute Tools (as defined therein), even to Partners; or

                  (ii) for themselves or on behalf of or through any third
         party, directly or indirectly, solicit, entice or persuade or attempt
         to solicit, entice or persuade any employees of or consultants to PBIO
         or its affiliates to terminate his or her employment with, consultancy
         to, or otherwise cease his or her relationship with PBIO or its
         affiliates for any reason.


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                  (b) Reasonableness of Restrictions. ChemGenics recognizes and
agrees that the specific but broad geographical scope of the foregoing
provisions is reasonable, legitimate and fair in view of PBIO's present strategy
and its future needs to market its products in a large geographic area in order
to have a sufficient customer base to make PBIO's business profitable.

         3. Protected Information. In addition to and without limiting the
confidentiality obligations set forth in the Confidentiality Agreement or the
License Agreement, PBIO shall at all times maintain in confidence and shall not,
without the prior written consent of ChemGenics use, disclose or give to others
any confidential information particular to or relating to the particular drug
discovery projects of the Drug Discovery Program.

         PBIO and ChemGenics acknowledge that during the term of this Agreement
each may have access to confidential and proprietary information of the other,
including tangible manifestations of technology (including, without limitation,
organisms (or parts thereof), cell lines, cultures, plasmids, clones, vectors,
reagents and DNA and progeny, reproductions and derivatives of any of them),
information, data, formulae, methods, processes, procedures, patents and ideas
and the like ("Proprietary Information"), provided that Proprietary Information
shall not include any item of tangible property, information, data, formula,
method, process, procedures, patents or ideas which:

         (a) is within the public domain prior to the time of disclosure to the
other or thereafter comes within the public domain, other than as a result of
disclosure by the recipient or any of its representatives in violation of this
Agreement;

         (b) was, on or before the date of disclosure to the recipient in the
possession of the recipient as evidenced by written records of the recipient; or

         (c) is acquired by the Recipient from a third party not under an
obligation of confidentiality to the disclosing party.

         The Parties shall use the Proprietary Information only as permitted by
the License Agreement or in connection with the transactions contemplated by the
Master Agreement.

         The Parties shall limit access to all Proprietary Information to their
employees, consultants and subcontractors who shall reasonably require access to
the Proprietary Information for the permitted use thereof.

         In the event that a party or anyone to whom it transmits the
Proprietary Information pursuant to this Agreement becomes legally required to
disclose any such Proprietary Information, such party shall provide the other
with prompt notice so that it may seek a protective order or other appropriate
remedy and/or waive compliance with the provisions of this Agreement. In the
event that such protective order or other remedy is not obtained, or that such

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party waives compliance with the provisions of this Agreement, the recipient
shall furnish only that portion of the Proprietary Information which is legally
required in the opinion of recipient's counsel.

         4. ChemGenics' Access to Technology of PBIO-Related Entities. As long
as the License Agreement remains in effect, PBIO shall use its reasonable
efforts to negotiate provisions in any entity, partnership, joint venture or
other off-balance-sheet financing vehicle in which PBIO owns or has the right to
acquire more than a de-minimus interest or to which PBIO is a party, either
directly or through any Affiliate (as defined in the License Agreement), to
afford ChemGenics access and rights for drug discovery purposes to technology
developed or acquired by any such entity, partnership, joint venture or other
off-balance-sheet financing vehicle, and PBIO agrees that PBIO's (and such
Affiliate's) rights in and to any such technology shall be included in the
Licensed Technology under the License Agreement to the extent permitted by any
such provisions.

         5. Severability Provision. If any term or provision of this Agreement
is held to be invalid or unenforceable under applicable law, such provision
shall be ineffective only to the extent of such invalidity or unenforceability,
without invalidating the remainder of such provision or the remaining provisions
of this Agreement. In furtherance of and not in limitation of the foregoing,
PBIO and ChemGenics expressly agree that if the duration of or geographical
extent of, or any of the business activities covered by, the non-competition
provisions of Sections 1 and 2 hereof are determined to be in excess of that
which is valid or enforceable under applicable law, then such provision shall be
construed to cover only that duration, extent or activities that may validly or
enforceably be covered. PBIO and ChemGenics acknowledge the uncertainty of the
law in this respect and expressly stipulate that this Agreement shall be
construed in a manner that renders its provisions valid and enforceable to the
maximum extent (not exceeding its express terms) possible under applicable law.

         6. Remedies. PBIO and ChemGenics acknowledge and agree that any breach
by PBIO, ChemGenics or their respective affiliates of the provisions of Sections
1 through 4 of this Agreement could cause irreparable damage. Accordingly, in
the event of any actual or threatened breach by PBIO, ChemGenics or their
respective affiliates of such provisions, the non-breaching party shall (in
addition to any other remedies that it may have) be entitled to a temporary
and/or permanent injunction or other equitable relief to enforce such
provisions. PBIO, ChemGenics or their respective affiliates hereby waive any
adequacy of remedy at law defense which such party may now or hereafter have in
the event of any breach by such party or its affiliates of the provisions of
Sections 1 through 4 of this Agreement.

         7. No Waiver of Rights, Powers and Remedies. No failure or delay by a
party hereto in exercising any right, power or remedy under this Agreement, and
no course of dealing between the parties hereto, shall operate as a waiver of
any such right, power or remedy of the party. No single or partial exercise of
any right, power or remedy under this Agreement by a

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party hereto, nor any abandonment or discontinuance of steps to enforce any such
right, power or remedy, shall preclude such party from any other or further
exercise thereof or the exercise of any other right, power or remedy hereunder.
The election of any remedy by a party hereto shall not constitute a waiver of
the right of such party to pursue other available remedies. No notice to or
demand on a party not expressly required under this Agreement shall entitle the
party receiving such notice or demand to any other or further notice or demand
in similar or other circumstances or constitute a waiver of the rights of the
party giving such notice or demand to any other or further action in any
circumstances without such notice or demand.

         8.       Miscellaneous.

         (a) Amendment and Waiver. This Agreement may be amended, and any term
or provision of this Agreement may be waived, only by written agreement of the
parties hereto.

         (b) Assignment. This Agreement shall be assignable only to any party to
whom the License Agreement is assigned, in accordance with the terms contained
therein.

         (c) Termination. This Agreement (other than Section 3) shall terminate
when and if the License Agreement terminates.

         (d) Governing Law. This Agreement and the rights and obligations of the
parties hereunder shall be construed in accordance with and governed by the laws
of the Commonwealth of Massachusetts, without giving effect to the conflict of
law principles thereof.

         (e) Jurisdiction and Service of Process. Any legal action or proceeding
with respect to this Agreement may be brought in the courts of the Commonwealth
of Massachusetts or of the United States of America for the District of
Massachusetts. By execution and delivery of this Agreement, each of the parties
to this Agreement hereto accepts for itself and in respect of its property,
generally and unconditionally, the jurisdiction of the aforesaid courts. The
parties hereby irrevocably waive any objection or defense that they may now or
hereafter have to the assertion of personal jurisdiction by any such court in
any such action or to the laying of the venue of any such action in any such
court, and hereby waive, to the extent not prohibited by law, and agree not to
assert, by way of motion, as a defense, or otherwise, in any such proceeding,
any claim that is not subject to the jurisdiction of the above-named courts for
such proceedings. Each of the parties hereto irrevocably consents to the service
of process of any of the aforementioned courts in any such action or proceeding
by the mailing of copies thereof by registered mail, postage prepaid, to any
party at its address set forth below and irrevocably waives any objection or
defense that it may now have or hereafter have to the sufficiency of any such
service of process in any such action.

         (f) Notices. All notices, requests, consents and other communications
hereunder shall be in writing, shall be addressed to the receiving party's
address set forth below or to such other

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address as a party may designate by notice hereunder, and shall be either (i)
delivered by hand, (ii) made by telex, telecopy or facsimile transmission, (iii)
sent by recognized overnight courier, or (iv) sent by registered or certified
mail, return receipt requested, postage prepaid.

         If to ChemGenics:          ChemGenics Pharmaceuticals Inc.
                                    One Kendall Square
                                    Building 300 - Third Floor
                                    Cambridge, MA  02139
                                    Attn: President

         With a copy to:            Jeffrey M. Wiesen, Esquire
                                    Mintz, Levin, Cohn, Ferris,
                                    Glovsky and Popeo, P.C.
                                    One Financial Center
                                    Boston, MA 02111
                                    Fax: (617) 542-2241

         If to PBIO:                PerSeptive Biosystems, Inc.
                                    500 Old Connecticut Path
                                    Framingham, MA  01701
                                    Attn: President

         With a copy to:            Rufus C. King, Esquire
                                    Testa, Hurwitz and Thibeault, L.L.P.
                                    125 High Street
                                    Boston, MA 02110
                                    Fax: (617) 248-7100

All notices, requests, consents and other communications hereunder shall be
deemed to have been (i) if by hand, at the time of the delivery thereof to the
receiving party at the address of such party set forth above, (ii) if made by
telex, telecopy or facsimile transmission, at the time that receipt thereof has
been acknowledged by electronic confirmation or otherwise, (iii) if sent by
overnight courier, on the next business day following the day such notice is
delivered to the courier service, or (iv) if sent by registered or certified
mail, on the fifth business day following the day such mailing is made.

         (g) Headings. The headings in the Sections and the paragraphs of this
Agreement are inserted for convenience only and shall not affect the meaning or
interpretation of this Agreement.


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         (h) Counterparts. This Agreement may be executed in one or more
counterparts, and by different parties hereto on separate counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.


              [THE REMAINDER OF THIS PAGE IS INTENTIONALLY BLANK.]


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         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first above written.

                                           CHEMGENICS PHARMACEUTICALS INC.


                                           By: /s/ Barry A. Berkowitz
                                               ---------------------------------
                                                  Barry A. Berkowitz, President



                                           PERSEPTIVE BIOSYSTEMS, INC.


                                           By: /s/ Noubar B. Afeyan
                                               ---------------------------------
                                                  Noubar B. Afeyan, President


Confidentiality and
Non-Competition Agreement

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