EXECUTION COPY

                            ASSET PURCHASE AGREEMENT

                           dated as of March 19, 1999,

                                  by and among

                          JBL SCIENTIFIC INCORPORATED,

                                 as the Seller,

                               GENTA INCORPORATED,

                          as Shareholder and Guarantor,

                                       and

                             JBL ACQUISITION CORP.,

                                  as the Buyer


<PAGE>

                                TABLE OF CONTENTS

                                                                        Page

ARTICLE I PURCHASE AND SALE OF ASSETS.....................................2
     1.1         Defined Terms............................................2
     1.2         Purchased Assets.........................................2
     1.3         Excluded Assets..........................................4
     1.4         Closing..................................................5
     1.5         Assets Not Assignable....................................5

ARTICLE II PURCHASE PRICE.................................................6
     2.1         Payment of the Purchase Price............................6
     2.2         Post-Closing Adjustment to Preliminary Purchase Price....6
     2.3         Purchase Price Allocation................................8
     2.4         Sales and Transfer Taxes.................................8
     2.5         Prorations...............................................8

ARTICLE III LIABILITIES...................................................8
     3.1         Assumption of Liabilities................................8
     3.2         Non-Assumption of Liabilities............................9
     3.3         Employee Benefit Plans...................................9

ARTICLE IV REPRESENTATIONS AND WARRANTIES OF THE SELLER AND SHAREHOLDER..10
     4.1         Ownership, Organization and Qualification...............10
     4.2         Authorization...........................................10
     4.3         Enforceability..........................................10
     4.4         Conflicting Obligations.................................10
     4.5         Subsidiaries............................................11
     4.6         Title to Assets.........................................11
     4.7         Third Party Consents....................................11
     4.8         Organizational Documents................................11
     4.9         Financial Statements....................................11
     4.10        Real Property; Leases...................................11
     4.11        Personal Property.......................................12
     4.12        All Necessary Assets....................................12
     4.13        Receivables.............................................12
     4.14        Inventories.............................................13
     4.15        Intellectual Property...................................13
     4.16        Insurance...............................................15
     4.17        Permits.................................................15
     4.18        Material Contract.......................................16
     4.19        Litigation..............................................17
     4.20        Compliance With Law.....................................17
     4.21        Environmental Matters...................................17


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     4.22        Contingent and Undisclosed Liabilities..................18
     4.23        Tax Matters.............................................19
     4.24        Employees; Labor Matters................................19
     4.25        Employee Benefit Plans..................................20
     4.26        Products Liability......................................21
     4.27        Product Warranty........................................21
     4.28        Events Subsequent to Latest Fiscal Year End.............21
     4.29        Customers and Suppliers.................................23
     4.30        Brokerage...............................................23
     4.31        Affiliate Transactions..................................24
     4.32        Guaranties..............................................24
     4.33        Investment..............................................24
     4.34        Commission Filings......................................24
     4.35        Amersham Termination....................................25
     4.36        Representations and Warranties True and Correct.........25

ARTICLE V REPRESENTATIONS OF THE BUYER...................................25
     5.1         Ownership, Organization and Qualification...............25
     5.2         Authorization...........................................25
     5.3         Enforceability..........................................26
     5.4         Conflicting Obligations.................................26
     5.5         Litigation..............................................26
     5.6         Brokerage...............................................26

ARTICLE VI COVENANTS OF THE SELLER AND THE SHAREHOLDER...................26
     6.1         Access..................................................26
     6.2         Operation of Business...................................27
     6.3         Preservation of Business................................27
     6.4         Insurance and Maintenance of Property...................27
     6.5         Compliance with Laws....................................27
     6.6         Supplemental Disclosure.................................27
     6.7         Fulfill Conditions......................................28
     6.8         Employees...............................................28
     6.9         Release of Liens........................................28
     6.10        Change of Corporate Name................................28
     6.11        Documents of Transfer...................................28
     6.12        Nondisclosure and Noncompetition Agreement..............28
     6.13        Other Deliveries........................................28
     6.14        Collection of the Receivables...........................29
     6.15        Exclusive Dealing.......................................29
     6.16        Further Assurances......................................29
     6.17        Brokerage...............................................30
     6.18        Quality Assurance Agreement.............................30
     6.19        Intellectual Property Assignments.......................30
     6.20        Lipid License Agreement.................................30
     6.21        Biogenex License Agreement..............................30


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     6.22        Note....................................................30
     6.23        On-Site Contamination...................................31
     6.24        The Seller's Welfare Plans..............................31
     6.25        The Seller's 401(k) Plan................................31

ARTICLE VII COVENANTS OF THE BUYER.......................................32
     7.1         Certified Resolutions...................................32
     7.2         Assignment, Bill of Sale and Assumption Agreement.......32
     7.3         Nondisclosure and Noncompetition Agreement..............32
     7.4         Quality Assurance Agreement.............................32
     7.5         Lipid License Agreement.................................32
     7.6         Note....................................................32
     7.7         Lease...................................................32
     7.8         Employees...............................................32
     7.9         Preservation of Records.................................33
     7.10        Uncollectible Receivables...............................33
     7.11        Access to Property......................................33
     7.12        The Buyer's 401(k) Plan.................................34
     7.13        The Buyer's Welfare Plans...............................34
     7.14        Employment Terms and Benefits after the Closing Date....35
     7.15        Product Liability Claims................................35
     7.16        Minimum Net Book Value..................................35

ARTICLE VIII CONDITIONS OF THE BUYER'S OBLIGATION TO CLOSE...............35
     8.1         Representation and Warranties...........................35
     8.2         Performance of Covenants and Obligations................36
     8.3         Proceedings and Instruments Satisfactory................36
     8.4         Adverse Change..........................................36
     8.5         No Litigation...........................................36
     8.6         Consents, Approvals, Certifications, Licenses 
                    and Permit...........................................36
     8.7         Good Standing Certificates..............................36
     8.8         Opinion of Counsel......................................36
     8.9         Due Diligence...........................................37
     8.10        Approval by the Shareholder's Shareholders..............37
     8.11        Lease...................................................37

ARTICLE IX CONDITIONS TO THE SELLER'S OBLIGATION TO CLOSE................37
     9.1         Representations and Warranties..........................37
     9.2         Performance of Covenants and Obligations................37
     9.3         Proceedings and Instruments Satisfactory................37
     9.4         No Litigation...........................................37
     9.5         Opinion of Counsel......................................38

ARTICLE X INDEMNIFICATION BY SELLER AND SHAREHOLDER......................38
     10.1        Indemnification.........................................38
     10.2        Procedures for Making Claims............................38


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     10.3        Participation in Defense of Third Party Claims..........39
     10.4        Survival of Representations and Indemnification.........39
     10.5        Limitations on Indemnifiable Damages....................40
     10.6        Offset..................................................40
     10.7        Other Indemnification Provisions........................40

ARTICLE XI INDEMNIFICATION BY BUYER......................................41
     11.1        Indemnification.........................................41
     11.2        Procedures for Making Claims............................41
     11.3        Participation in Defense of Third Party Claims..........42
     11.4        Survival of Indemnification.............................42
     11.5        Limitations on Indemnifiable Damages....................43
     11.6        Offset..................................................43
     11.7        Other Indemnification Provisions........................43

ARTICLE XII TERMINATION..................................................44
     12.1        Rights to Terminate.....................................44
     12.2        Effects of Termination..................................44

ARTICLE XIII GUARANTEE...................................................44
     13.1        Guarantee by the Shareholder............................44
     13.2        Guarantee by Promega....................................45

ARTICLE XIV DEFINITIONS..................................................45
     14.1        Certain Defined Terms...................................45
     14.2        Interpretation..........................................53
     14.3        Other Terms.............................................53

ARTICLE XV MISCELLANEOUS.................................................53
     15.1        Survival of Representations and Warranties..............53
     15.2        Benefit and Assignment..................................53
     15.3        Governing Law...........................................53
     15.4        Expenses................................................53
     15.5        Notices.................................................53
     15.6        Counterparts............................................54
     15.7        Headings................................................54
     15.8        Amendment, Modification and Waiver......................54
     15.9        Entire Agreement........................................54
     15.10       Third-Party Beneficiaries...............................55
     15.11       Publicity...............................................55


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EXHIBITS:
     Exhibit A-1    Form of Legal Opinion of Kramer Levin Naftalis & Frankel LLP
     Exhibit A-2    Form of Legal Opinion of Sinsheimer, Schiebelhut & Baggett
     Exhibit A-3    Form of Legal Opinion of Michael Best & Friedrich LLP
     Exhibit B      Form of Assignment, Bill of Sale and Assumption Agreement
     Exhibit C-1    Form of Seller Intellectual Property Assignment
     Exhibit C-2    Form of Shareholder Intellectual Property Assignment
     Exhibit D      Summary of Lease Terms
     Exhibit E      Form of Lipid License Agreement
     Exhibit F      Form of Nondisclosure and Noncompetition Agreement
     Exhibit G      Form of Note
     Exhibit H      Form of Quality Assurance Agreement

SCHEDULES:
     Schedule 1.2(e) - Real Estate
     Schedule 1.2(f) - Equipment
     Schedule 1.2(g) - Vehicles
     Schedule 1.3(h) - Shareholder  Tangible  Personal  Property 
     Schedule 1.3(n) - Excluded  Assets  
     Schedule 2.3 - Purchase Price  Allocation
     Schedule 4.5 -  Subsidiaries  
     Schedule 4.7 - Third Party  Consents
     Schedule 4.8 -  Organization  Documents  
     Schedule 4.9 -  Financial Statements  
     Schedule 4.10(a) - Real Estate 
     Schedule 4.11 - Personal Property 
     Schedule 4.13 - Receivables 
     Schedule 4.15(b) - Infringement of Intellectual Property 
     Schedule 4.15(c) - Patents 
     Schedule 4.15(d) - Permits  
     Schedule 4.15(e) -  Misappropriation  
     Schedule 4.16(a) - Insurance  Policies  
     Schedule 4.16(c) - Insurance  Claims  
     Schedule 4.16(d) -  Self-Insurance  
     Schedule 4.17 - Permits  
     Schedule 4.18 - Material  Contracts and Other Descriptions and Lists 
     Schedule 4.19 - Litigation  
     Schedule 4.20 - Compliance  With Law 
     Schedule 4.21(a) - Environmental Compliance 
     Schedule 4.21(c) - Environmental Litigation
     Schedule 4.21(d) - Disposal  Practices  
     Schedule 4.24(a) - Employees
     Schedule 4.25(a) - Employee Benefit Plans 
     Schedule 4.25(g) - Family and Medical  Leave Act 
     Schedule 4.28 - Subsequent  Events  


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     Schedule 4.29 - Customers  and Suppliers  
     Schedule 4.30 - Brokerage  
     Schedule 4.31 - Affiliate  Transactions 
     Schedule 4.33 - Bank Accounts;  Power of Attorney; Other 
     Schedule 7.8 - Retained Employees


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<PAGE>

                            ASSET PURCHASE AGREEMENT


            THIS ASSET PURCHASE  AGREEMENT (this "Agreement") is entered into as
of the 19th day of March,  1999, by and among JBL ACQUISITION CORP., a Wisconsin
corporation (the "Buyer"), JBL SCIENTIFIC INCORPORATED, a California corporation
(the "Seller"), and GENTA INCORPORATED,  a Delaware corporation,  being the sole
shareholder of the Seller (the "Shareholder").

                                    RECITALS

            WHEREAS,  the Seller is engaged in the development,  manufacture and
sale  of  specialty  chemical  products,  including  DNA  reagents  used  in the
synthesis of oligomers (the "Business");

            WHEREAS,  the Seller leases and uses certain real property and owns,
leases and uses certain  tangible and  intangible  assets used in the  Business,
including,   without   limitation,    intellectual   property,   buildings   and
improvements,  machinery and equipment, vehicles, inventory, contract rights and
prepaid expenses and receivables;

            WHEREAS,  the Buyer desires to purchase all of the assets related to
the Business other than the Excluded Assets referred to below and to assume only
certain  specific  liabilities  associated  with the  Business,  and the  Seller
desires to sell and  transfer to the Buyer those assets and  liabilities,  while
retaining  environmental and all other liabilities,  all as more fully set forth
below;

            WHEREAS,  the  Shareholder,  in  consideration  of the sale of those
assets  and the  assumption  of  those  liabilities,  agrees  to be party to the
Agreement  and  to  guarantee  the  Seller's  performance  and  each  and  every
obligation of the Seller under this Agreement and the transactions  contemplated
hereby; and

            WHEREAS,  Promega Corporation,  a Wisconsin corporation ("Promega"),
in  consideration  of the purchase of those assets and the  assumption  of those
liabilities,  is willing to guarantee the Buyer's  payment of the Purchase Price
(as defined by below), including the payments of obligations under the Note, the
Buyer's  obligations  under  the  Lease  (as  defined  below)  and  the  Buyer's
obligations under the Quality Assurance Agreement.

            NOW,  THEREFORE,  in consideration of the foregoing recitals and the
mutual  agreements  and  covenants  contained  herein,  and for  other  good and
valuable  consideration,  the  receipt  and  sufficiency  of  which  are  hereby
acknowledged,  the Buyer, Promega, the Seller and the Shareholder,  hereby agree
as follows:


<PAGE>

                                    ARTICLE I

                           PURCHASE AND SALE OF ASSETS

            1.1 Defined Terms.  Capitalized  terms used herein have the meanings
set forth in Section 13.1.

            1.2 Purchased  Assets.  Subject to the terms and  conditions of this
Agreement, and in reliance upon the representations,  warranties,  covenants and
agreements  made in this Agreement by the Buyer,  the Seller and the Shareholder
(1) the Buyer shall purchase, accept and acquire from the Seller, and the Seller
shall sell, transfer, convey, assign and deliver to the Buyer, all of its right,
title and  interest  in and to the assets  and  properties  of the  Seller  (but
excluding  Excluded Assets) used or held in the conduct of or in connection with
the Business,  whether  tangible or  intangible,  real,  personal or mixed,  and
wherever  located  (the  "Seller  Purchased  Assets"),  and (2) the Buyer  shall
purchase,  accept and acquire from the  Shareholder,  and the Shareholder  shall
sell, transfer, convey, assign and deliver to the Buyer, all of its right, title
and interest in and to the assets and properties of the Shareholder specified in
Section 1.2(o) (the  "Shareholder  Purchased  Assets";  together with the Seller
Purchased Assets, the "Purchased Assets"). The Purchased Assets include, without
limitation,  the Seller's or, in the case of Section 1.2(o),  the  Shareholder's
right, title and interest in and to the following,  except as otherwise provided
in Sections 1.3, 1.5 and 3.3.

          (a)  All  Intellectual   Property  of  the  Seller  and  all  goodwill
               associated  with the  foregoing,  all  goodwill  associated  with
               respect  thereto,  licenses and sublicenses  granted and obtained
               with  respect  thereto and rights  thereunder,  remedies  against
               infringements  thereof  and  rights to  protection  of  interests
               therein under the laws of all jurisdictions;

          (b)  All retail and  non-retail  inventories of the Seller of whatever
               kind,  including,  without  limitation,   merchandise,  supplies,
               accessories,  finished goods,  work-in-process  and raw materials
               (the "Inventories");

          (c)  All present and future  rights of the Seller to payment for goods
               sold or services  rendered  whether or not earned by performance,
               including,   without   limitation,   trade  and  other   accounts
               receivable, all notes receivable and all other amounts receivable
               (the "Receivables");

          (d)  All prepaid expenses,  advance  payments,  deposits and rights to
               receive discounts, refunds, rebates, awards and the like;

          (e)  All leaseholds and subleaseholds, and improvements,  fixtures and
               appurtenances  thereto,  including,  without  limitation,  leases
               relating  to the  parcels of land with the legal  description  of
               which  is   described   on  Schedule   1.2(e)   attached   hereto
               (collectively, the "Real Estate");

          (f)  All  equipment   (building  or  office),   machinery,   reactors,
               lyophilizers,   chemical  manufacturing  equipment,   prototypes,
               parts, components,  projects in process,  


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<PAGE>

               furniture, appliances, artwork, computers, computer terminals and
               printers, telephone systems, telecopiers and photocopiers, office
               supplies  and  office  equipment  and  other  tangible   personal
               property of every kind and description, which are owned or leased
               by the Seller,  or are utilized in connection with the operations
               of the  Business  upon or  within  the  Real  Estate,  including,
               without  limitation,   those  items  listed  on  Schedule  1.2(f)
               attached  hereto,  but excluding the Inventories and the Vehicles
               (the "Equipment");

          (g)  All motor vehicles,  including,  without limitation, those listed
               on Schedule 1.2(g) attached hereto (the "Vehicles");

          (h)  All contracts, leases, subleases,  arrangements,  commitments and
               other  agreements of the Seller (other than the Granada  Leases),
               including,  without limitation,  all customer agreements,  vendor
               agreements,   purchase   orders,   installation  and  maintenance
               agreements,  hardware lease or rental agreements, contract claims
               and all other  arrangements  and  understandings  related  to the
               Business,  including,  without limitation,  those items which are
               listed on Schedule 4.18 (the "Contracts");

          (i)  All   qualifications,    registrations,    filings,   privileges,
               franchises,  immunities,  licenses,  permits,  authorizations and
               approvals issued by Governmental  Authorities to the Seller which
               are used or  required  in order for the Seller to own and operate
               the Business,  including, without limitation, all certificates of
               occupancy  and  certificates,  licenses  and permits  relating to
               zoning, building,  housing, safety,  Environmental Laws, fire and
               health (the "Permits");

          (j)  All Records;

          (k)  All  sales,  marketing  and  expansion  plans,  strategic  plans,
               projections,  studies,  reports  and  other  documents  and  data
               (including, without limitation,  creative materials,  advertising
               and promotional  matters and current and past lists of customers,
               suppliers,  vendors and sources) related to the Business, and all
               training  materials  and  marketing   brochures  related  to  the
               Business;

          (l)  The Seller's goodwill related to the Business;

          (m)  All of the  Seller's  rights  and  remedies,  under  warranty  or
               otherwise, against a manufacturer, vendor or other Person for any
               defects in any Purchased Asset;

          (n)  All  deposits  held by the Seller with  respect to services to be
               performed or products to be delivered after the Closing;

          (o)  All patents,  patent applications and other Intellectual Property
               of  the  Shareholder  set  forth  in  the  Intellectual  Property
               Assignment made by the Shareholder in favor of the Buyer;

          (p)  All other properties,  assets and rights of every kind, character
               or  description  which 


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<PAGE>


               are owned by the Seller and which are not Excluded Assets; and

          (q)  All  causes of action,  choses in action  and rights of  recovery
               with respect to any of the foregoing.

            1.3 Excluded Assets. The Purchased Assets shall not include, and the
Seller shall retain, the following assets (the "Excluded Assets"):

          (a)  The Seller's rights under this Agreement;

          (b)  The  Seller's  minute  books,   stock  record  books,   corporate
               franchise  and   authorizations  to  do  business  as  a  foreign
               corporation and tax returns;

          (c)  The Seller's cash and cash equivalents;

          (d)  The Seller's environmental policies and procedures;

          (e)  All bank or investment accounts of the Seller;

          (f)  All  causes of action,  choses in action  and rights of  recovery
               that may arise in connection  with the discharge by the Seller of
               any Excluded  Liability or rights of recovery or  contribution in
               respect of any Excluded Liability;

          (g)  Any claims of the Seller  for  refunds of income and other  taxes
               attributable to periods prior to the closing;

          (h)  All  tangible   personal  property  of  the  Shareholder  in  the
               possession  of the  Seller,  all of which is listed  on  Schedule
               1.3(h);

          (i)  All Records relating to Excluded Assets or Excluded Liabilities;

          (j)  Any  Intellectual  Property and know-how  related to  therapeutic
               applications of antisense  technology,  including but not limited
               to, manufacturing, storage, packaging, handling, distribution and
               quality control  information  related to compound G3139;  control
               oligonucleotides related to G3139; phosphorothioates and modified
               backbone  structures  and  components  thereof  related to G3139;
               analytical  testing  and  control  information  relating  to such
               compounds;  stability  information  and  information  relating to
               preclinical   and  clinical   development  and  testing  of  such
               compounds; and all written Records pertaining to the above;

          (k)  The Granada Leases;

          (l)  Employee-related assets not being assumed by the Buyer;

          (m)  All insurance policies of the Seller;


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<PAGE>

          (n)  All assets listed on Schedule 1.3(n); and

          (o)  All rights and obligations under the Granada Leases.

            Nothing in this  Section  1.3 shall  prevent the  concurrent  use of
know-how by the Buyer to the extent such  know-how is necessary  and  sufficient
for the Buyer to assume control of and to conduct the Business.

            1.4 Closing. The closing (the "Closing") of the purchase and sale of
the Purchased  Assets shall take place at 10:00 a.m., local time, on the Closing
Date, at the offices of Michael Best & Friedrich LLP, One South Pinckney Street,
Suite 700,  Madison,  Wisconsin 53703, or at such other time and place as may be
mutually  agreed to by the Buyer and the Seller.  The  "Closing  Date" means the
second  business day following the  satisfaction  or waiver of all conditions to
the  obligations  of the parties to  consummate  the  transactions  contemplated
hereby (other than conditions with respect to action the respective parties will
take at the  Closing),  or such other date as may be  mutually  agreed to by the
Buyer and the Seller.  The Closing  shall be  effective  as of 12:01 a.m. on the
Closing Date; provided, however, that the Buyer shall have no further obligation
under this  Agreement if the  conditions set forth in Article VIII have not been
satisfied  by the Seller or  expressly  waived by the Buyer on or before May 15,
1999.

             1.5 Assets Not Assignable.

            (a) To the extent that any interest in any of the  Purchased  Assets
is not capable of being assigned,  transferred or conveyed  without the consent,
waiver or authorization of any Person and that consent,  waiver or authorization
is not  obtained,  or if such  assignment,  transfer or  conveyance or attempted
assignment,  transfer or conveyance would constitute a breach of any Contract or
other  Purchased  Asset,  or a  violation  of any law,  statute,  decree,  rule,
regulation  or  other  governmental  edict  or is not  immediately  practicable,
notwithstanding  anything to the contrary contained herein, this Agreement shall
not  constitute an assignment,  transfer or conveyance of such  interest,  or an
attempted  assignment,  transfer or conveyance of such interest (such  interests
being  hereinafter  collectively  referred to as  "Restricted  Interests").  The
entire  beneficial  interest in any Purchased Assets subject to a restriction as
described  above,  and any other  interest in such Purchased  Assets,  which are
transferable  notwithstanding  such  restriction,  shall be transferred from the
Seller to the Buyer as provided in this Section 1.5.

            (b) Anything in this Agreement to the contrary notwithstanding,  the
Seller shall not be obligated to transfer to the Buyer any Restricted  Interests
without the Buyer or the Seller first having obtained all consents,  waivers and
authorizations  necessary for such transfers.  In consultation with the Buyer as
to the  practicalities of proposed actions,  the Seller shall use its reasonable
efforts  to  assist  the  Buyer  in  obtaining   such   consents,   waivers  and
authorizations and to resolve any  impracticalities of assignment referred to in
Section 1.5(a) hereof.

            (c) To the extent  that the  consents,  waivers  and  authorizations
referred  to in  Section  1.5(a)  hereof  are not  obtained  by the Buyer or the
Seller,  or until the  impracticalities  of  transfer  referred  to therein  are
resolved,  the Seller shall use reasonable  efforts to (i) provide to the Buyer,
at the request of the Buyer and at the  Seller's  expense,  the  benefits of any
Restricted  


                                      -5-


<PAGE>

Interests,  (ii)  cooperate in reasonable  and lawful  arrangements  designed to
provide  such  benefits  to the Buyer and (iii)  enforce,  at the request of the
Buyer for the account of the Buyer,  any rights of the Seller  arising  from any
Restricted  Interests  (including  the right to elect to terminate in accordance
with the terms thereof upon the request of the Buyer).

                                   ARTICLE II

                                 PURCHASE PRICE

             2.1 Payment of the Purchase Price.

            (a) The payment by the Buyer to the Seller for the Purchased  Assets
on the Closing Date (the "Preliminary  Purchase Price") shall be SIX MILLION TWO
HUNDRED  THOUSAND  DOLLARS  ($6,200,000)  payable  on the  Closing  Date  in the
following manner:

                     (i)    The delivery of the Note in an  aggregate  principal
                            amount of ONE MILLION TWO HUNDRED  THOUSAND  DOLLARS
                            ($1,200,000);

                     (ii)   TWO HUNDRED FIFTY THOUSAND DOLLARS ($250,000) of the
                            Preliminary Purchase Price (the "Adjustment Amount")
                            shall be retained by the Buyer until any  adjustment
                            to the  Preliminary  Purchase Price is determined in
                            accordance with Section 2.2; and

                     (iii)  The balance of the Preliminary  Purchase Price shall
                            be paid in cash to the Seller.

             (b) The amounts paid in cash pursuant to Section 2.1(a) shall be by
wire transfer of same-day funds to an account designated in writing to the Buyer
by the Seller prior to the Closing.

             2.2 Post-Closing Adjustment to Preliminary Purchase Price.

             (a) Purchase  Price  Adjustment.  The  Preliminary  Purchase  Price
assumes the Net Book Value of the  Purchased  Assets on the Closing Date will be
at least $1,768,000 (the "Estimated Net Book Value").  The Preliminary  Purchase
Price  shall be reduced  on a  dollar-for-dollar  basis by the  amount  that the
actual Net Book Value of the Purchased Assets  determined as of the Closing Date
and reflected on the Closing  Balance Sheet (the "Final Net Book Value") is less
than the Estimated Net Book Value. The Preliminary Purchase Price, as reduced by
this Section 2.2, is the "Purchase Price."

             (b) Net Book Value. As used herein, the term "Net Book Value" shall
mean the book value of the Purchased  Assets  calculated in accordance with GAAP
on a basis consistent with the preparation of the Financial  Statements less the
value  of the  Operating  Accruals;  provided,  however,  the  Purchased  Assets
acquired  pursuant  to the  Biogenex  License  Agreement  shall not  include any
increases in the assets  attributable  to any  payments  made under such license
after December 31, 1998;  provided,  further,  such definition is modified as to
Inventories as set forth in 


                                      -6-


<PAGE>

the following sentence. Inventories shall be valued on the basis of the lower of
cost  (first-in,  first-out)  or market in accordance  with GAAP,  excluding the
following:  (a) all  slow-moving,  obsolete or damaged  merchandise  included in
reserves  established on a basis  consistent with the  Inventories  shown on the
Latest  Balance  Sheet;  (b) items with an  expiration  date prior to the twelve
month  anniversary  of the Closing  Date;  (c) products that do not meet current
quality standards and  specifications  of the Seller;  and (d) finished goods in
quantities  on  hand in  excess  of  quantities  sold  in the  twenty-four  (24)
preceding months up to and including the Closing Date.

             (c) Closing Balance Sheet. Within sixty (60) days after the Closing
Date,  the Buyer shall cause Ernst & Young LLP (the  "Buyer's  Accountants")  to
prepare  a draft  audited  balance  sheet  of the  Business  as of the  close of
business  on the  Closing  Date  in  accordance  with  GAAP  applied  on a basis
consistent  with the  preparation  of the  Financial  Statements  (the  "Closing
Balance  Sheet").  The  Closing  Balance  Sheet  shall  consist  solely of those
Purchased Assets and the Operating  Accruals  normally  included in the Seller's
historical  balance sheets.  For purposes of measuring the carrying value of any
element of the Closing  Balance Sheet,  the assets and  liabilities  referred to
above will be presented as though the transactions  contemplated  herein had not
occurred and in accordance with GAAP consistently applied by the Seller.

             (d)  Dispute   Resolution.   The  Closing  Balance  Sheet  and  any
supporting  documentation  may be  reviewed by a firm of  independent  certified
public  accountants  selected by the Seller  (the  "Seller's  Accountants").  In
connection  with the  preparation  of the  Closing  Balance  Sheet,  the Buyer's
Accountants  shall conduct a physical count of the Inventories as of the Closing
Date. The Seller's Accountants may audit the work papers used in the preparation
of the Closing Balance Sheet, and the Seller shall grant the Buyer's Accountants
full access to all work papers and other  documents and  information  and to all
personnel as may be reasonably requested. If the Seller has any objection to the
draft Closing  Balance Sheet, it shall deliver a detailed  statement  describing
its  objection to the Buyer within  thirty (30) days after  receiving  the draft
Closing Balance Sheet.  The Buyer and the Seller shall meet (if necessary) in an
attempt to  stipulate  to the  purchase  price  adjustment  described in Section
2.2(a) (or  stipulate to such portion  thereof with respect to which there is no
dispute).  If the parties do not agree upon a final  resolution  within  fifteen
(15) days after the Buyer has  received  the  Seller's  objections,  the Buyer's
Accountants and the Seller's  Accountants  shall mutually select a third firm of
independent  public  accountants  (the  "Dispute  Accountants")  to resolve  any
remaining  objections.  The  determination of the Dispute  Accountants  shall be
binding on the parties.  The Buyer and the Seller shall pay equally all fees and
expenses of the Dispute  Accountants.  No party may  unreasonably  withhold  its
consent to the  appointment  as  Dispute  Accountants  of a firm of  independent
accountants suggested by another party.

            (e)  Modification of the Closing Balance Sheet. If the Buyer and the
Seller  agree  upon a  change  to the  Closing  Balance  Sheet,  or the  Dispute
Accountants  determines  that a change  should  be made to the  Closing  Balance
Sheet,  the  Buyer  shall  promptly  cause  the  Buyer's  Accountants  to modify
appropriately the Closing Balance Sheet. All references in this Agreement to the
Closing Balance Sheet, other than in Section 2.2(c), 2.2(d) and 2.2(e), shall be
to the Closing Balance Sheet as initially  prepared by the Buyer and accepted by
the Seller,  or to the Closing  Balance Sheet as modified by the Seller pursuant
to  agreement  of the Buyer and the  Seller or a  determination  of the  Dispute
Accountants, as applicable.

            (f) Payment of Purchase Price  Reduction.  After the Closing Balance
Sheet is in final  


                                      -7-


<PAGE>

form, if the Final Net Book Value reflected on the Closing Balance Sheet is less
than the Estimated Net Book Value,  then the Buyer shall retain such  difference
from the Adjustment  Amount.  If the Final Net Book Value as of the Closing Date
is greater than the Estimated Net Book Value, no adjustment shall be made. After
deducting any adjustments to the Preliminary Purchase Price as set forth in this
Section  2.2(f),  the Buyer shall pay the remainder of the Adjustment  Amount to
the Seller in same day funds on the day following  the date the Closing  Balance
Sheet is in final form. In the event of a dispute  regarding the Closing Balance
Sheet,  any undisputed  amounts shall be promptly paid, and any disputed amounts
shall be promptly paid upon resolution of the dispute.

            2.3 Purchase  Price  Allocation.  The parties  agree to allocate the
Purchase  Price as set forth on Schedule  2.3 for all  federal,  state and local
income  tax  purposes   (including  IRS  Form  8594),  and  will  not  take  any
inconsistent or contrary position therewith for any other purpose.

            2.4 Sales  and  Transfer  Taxes.  The  Seller  shall pay any and all
transfer, sales, purchase, use, value added, excise or similar tax imposed under
the laws of the United States,  or any state or political  subdivision  thereof,
which  arises  out of the  transfer  by the  Seller  to the  Buyer of any of the
Purchased Assets.

             2.5 Prorations.

            (a) Real and personal  property  taxes for the Purchased  Assets for
1999 shall be  prorated on the Closing  Date based upon the taxes  assessed  for
1999; but if the taxes assessed for 1999 are not known on the Closing Date, such
taxes  shall be  prorated  based upon the taxes  assessed  for 1998 and shall be
re-prorated  within ten (10) days after the 1999 tax  assessment  and rate shall
become available with appropriate payment made.

            (b) The Seller shall order final readings for utility services, such
as gas,  electricity,  water and sewer  services,  as of the  Seller's  close of
business  on the day before the  Closing  Date,  and  prorated  charges for such
utility services shall be reflected on the Closing Balance Sheet.

                                   ARTICLE III

                                   LIABILITIES

            3.1 Assumption of Liabilities.  As additional  consideration for the
Purchased  Assets,  the Buyer shall,  on the Closing  Date, by its execution and
delivery of the Assignment,  Bill of Sale and Assumption  Agreement,  assume and
agree to pay when due and perform when required only the following (the "Assumed
Liabilities"):

              (a)    all current  liabilities of the Seller  classified as trade
                     payables or operating  accruals as set forth on the face of
                     the  Closing  Balance  Sheet  (rather  than  in  any  notes
                     thereto);

              (b)    all written and oral  obligations  of the Seller  under the
                     Contracts  which   constitute   Purchased  Assets  and  all
                     obligations  under written and oral Contracts  entered into


                                      -8-


<PAGE>

                     by the Seller in the  Ordinary  Course of Business  between
                     the date of this  Agreement  and the Closing Date and which
                     do not violate any  covenant in this  Agreement,  but as to
                     any  obligation,  only to the  extent  that  payment is for
                     goods,  services or other  consideration  to another  party
                     that are  delivered,  performed or provided on or after the
                     Closing Date; and

              (c)    accrued  vacation  owing to employees of the Seller up to a
                     maximum of four weeks per employee.

provided,  however, that the Buyer shall not assume any obligation to the extent
the existence  thereof  violates or is in breach of any of the  representations,
warranties and covenants of the Seller or the Shareholder in this Agreement.

            3.2 Non-Assumption of Liabilities. Except only as expressly provided
in Section 3.1, the Buyer shall not be responsible  for, assume,  pay,  perform,
discharge, or accept any liabilities,  debts or obligations of the Seller of any
kind  whatsoever,  whether  actual,  contingent,   accrued,  known  or  unknown,
including,   without  limitation,   any  relating  to   interest-bearing   debt,
intercompany  indebtedness  owing from the Seller to the  Shareholder,  notes to
Affiliates  or other  related  Persons,  interest and  termination  penalties on
indebtedness, taxes, employee compensation,  severance, pension, profit-sharing,
vacation  in excess of four weeks per  employee,  health  insurance,  disability
insurance or other employee benefit plans and programs,  worker's  compensation,
breach or negligent  performance of any contract, or breach of warranty relating
thereto,  liabilities  resulting  from  breach of  contract,  torts  (including,
without  limitation,  product  liability  claims),  illegal  activity,  unlawful
employment or business practice,  infringement of intellectual  property rights,
claim for  environmental  liability  or  remediation  or any other  liability or
obligation whatsoever.  All such non-assumed liabilities,  debts and obligations
(collectively,  the "Excluded  Liabilities")  shall remain the responsibility of
the Seller which shall pay and discharge the same when and as due.

            3.3 Employee  Benefit  Plans.  The Buyer shall not assume,  honor or
accept any employee  benefit plan or stock option plan of the Seller,  including
but not  limited to any  employee  pension  benefit  plan  within the meaning of
Section 3(2) of ERISA.  Except for the  obligation  of the Buyer with respect to
accrued  vacation  set  forth in  Section  3.1(c)  and  except  for  liabilities
resulting from any failure by the Buyer to meet its  obligations  under Sections
7.8 or 7.13 of this  Agreement,  the  Seller  shall be  solely  responsible  for
satisfying all obligations  (whether arising under federal,  state or local law,
or pursuant to  contract)  which may arise or which may have arisen prior to the
Closing,  in  connection  with the  employment  by the  Seller  of the  Seller's
employees,  the creation,  funding or operation of any of the Seller's  employee
benefit plans that cover any of the Seller's employees,  or which may arise as a
result of the  transactions  described  in this  Agreement,  but  excluding  any
liabilities  incurred by the Seller as a result of the  Buyer's  failure to meet
its obligations under Sections 7.8 or 7.13 of this Agreement.

                                   ARTICLE IV

                         REPRESENTATIONS AND WARRANTIES

                          OF THE SELLER AND SHAREHOLDER


                                      -9-


<PAGE>

            In order to  induce  the  Buyer  and  Promega  to  enter  into  this
Agreement,  the Seller and the  Shareholder,  jointly  and  severally,  make the
following  representations  and  warranties  to the  Buyer  and  Promega  (which
representations  and warranties shall survive the Closing to the extent provided
in Section 10.4), each of which shall be deemed to be independently material and
relied upon by the Buyer and Promega,  regardless of any investigation  made by,
or  information  known to, the Buyer and  Promega.  Any matter  described on the
disclosure  schedules attached hereto and incorporated herein shall be set forth
with  reference to each separate  Section of this  Agreement to which the matter
relates.

            4.1 Ownership,  Organization and  Qualification.  The Seller and the
Shareholder are  corporations  duly  incorporated and in good standing under the
laws of the State of California  and the State of Delaware,  respectively,  have
not filed articles of dissolution and have a perpetual period of existence. Each
of the Seller and the  Shareholder  are  qualified  to  transact  business  as a
foreign  corporation  in  the  jurisdictions  where  it  is  required  to  be so
qualified,  except  where  such  failure to be  qualified  would not result in a
Material Adverse Effect.

            4.2 Authorization. The Seller and the Shareholder have all necessary
power and  authority  to enter into and  perform the  transactions  contemplated
hereby in accordance  with the terms and  conditions  hereof.  The execution and
delivery of this  Agreement,  and the  performance  by the Seller of each of its
obligations  contained herein, have been duly approved by the Board of Directors
of the Seller and the Shareholder,  and by the  Shareholder,  in its capacity as
sole shareholder of the Seller.  No other corporate  authorization by either the
Seller  or the  Shareholder  (including,  without  limitation,  approval  by the
Shareholder's  shareholders)  is required for the execution and delivery of this
Agreement or the  performance  by each of the Seller and the  Shareholder of its
obligations hereunder.

            4.3 Enforceability. Assuming the execution and delivery by the Buyer
and Promega have been duly  authorized,  this Agreement and all other agreements
of the Seller or the Shareholder  contemplated hereby are or, upon the execution
and delivery  thereof will be, the valid and binding  obligations  of the Seller
and the Shareholder,  respectively,  enforceable against them in accordance with
their terms.

            4.4  Conflicting  Obligations.  The  execution  and delivery of this
Agreement  does  not,  and the  consummation  of the  sale and  purchase  of the
Purchased  Assets will not: (a) conflict  with or violate any  provisions of the
certificate of incorporation or bylaws of each of the Seller or the Shareholder,
as  amended  and in  effect  on and as of the date  hereof  and on and as of the
Closing Date;  (b) conflict with or violate any  provisions of, or result in the
maturation or acceleration  of, any obligations  under any contract,  agreement,
instrument,  document,  lease, license, permit, indenture, or obligation, or any
law, statute,  ordinance, rule, regulation,  code, guideline, order, arbitration
award,  judgment or decree, to which the Seller or the Shareholder is subject or
to  which  the  Seller  or  the  Shareholder  is a  party;  or (c)  violate  any
restriction or limitation, or result in the termination or loss of any right (or
give any third Person the right to cause such  termination or loss), of any kind
to which the Seller or the Shareholder is bound, except, with respect to clauses
(b) and (c),  where  such  conflict,  violation  or loss  would not  result in a
Material Adverse Effect on the Business.


                                      -10-


<PAGE>

            4.5  Subsidiaries.  Except as set forth on Schedule  4.5, the Seller
owns no stock or other  securities of nor has any investment in any corporation,
joint  venture,  partnership  or other  business  enterprise.  The Seller has no
Subsidiaries.

            4.6 Title to Assets.  The Seller has good title to all of the Seller
Purchased  Assets and the  Shareholder  has good title to all of the Shareholder
Purchased Assets, in each case, free and clear of any Lien (other than Permitted
Liens).

            4.7 Third Party  Consents.  Except as set forth on Schedule  4.7, no
third  party  consents,  approvals  or  authorizations  are  necessary  for  the
execution and consummation of the transactions  contemplated hereby, nor are any
such  consents,  approvals  or  authorizations  required in order for any of the
Purchased Assets,  including without limitation,  the Contracts and the Permits,
to be assigned to the Buyer.

            4.8  Organizational  Documents.  Attached as Schedule  4.8 are true,
correct and complete  copies of the certificate of  incorporation  and bylaws of
the Seller and the Shareholder,  in each case as amended and in effect on and as
of the date hereof.

            4.9  Financial  Statements.  Attached as Schedule  4.9 are  complete
copies of the  unaudited  financial  statements  (including  December  31,  1998
balance  sheets and statements of earnings and cash flow) of the Seller for each
of its last three fiscal years ending December 31 through and including December
31, 1998 (the "Latest  Fiscal Year End"),  and a complete  copy of the unaudited
financial  statements  (including  balance  sheets and statement of earnings and
cash flow) of the Seller for the 2-month  period  ending  February 28, 1999 (the
"Latest Balance Sheet Date")  (collectively,  the "Financial  Statements").  The
Financial  Statements  have been prepared in accordance with GAAP maintained and
applied on a consistent  basis  throughout  the  indicated  periods,  and fairly
present  in all  material  respects  the  financial  condition  and  results  of
operation  of the Seller at the dates and for the  relevant  periods  indicated.
True and correct  copies  have been  delivered  to Buyer of all written  reports
submitted to the Seller or the Shareholder by the  Shareholder's  auditors since
January 1, 1994,  relating to the findings of audits or examination of the books
and  records of the  Seller and the  Shareholder;  provided,  that such  written
reports shall be redacted so that they shall include only those items related to
the Seller.


                                      -11-


<PAGE>

            4.10  Real  Property;  Leases.  The  Seller  does  not own any  real
property.  Schedule 4.10(a) sets forth a true and correct summary description of
all Real Estate leased or rented by the Seller.  The  description of each parcel
of Real Estate  describes such parcel fully and adequately.  To the Knowledge of
the Seller and the  Shareholder,  except as set forth on Schedule  4.10(a),  all
buildings,  structures  and other  improvements  on the Real  Estate are free of
defects that would result in loss to the Business in excess of $25,000.  The use
and operation of the Real Estate  conform to all  applicable  building,  zoning,
safety,  and  other  laws,  statutes,  ordinances,  rules,  regulations,  codes,
licenses,  material permits,  and all other restrictions and conditions,  except
where the failure to conform would not result in a Material  Adverse Effect.  To
the Knowledge of the Seller and the  Shareholder,  no portion of any of the Real
Estate is located in a flood  plain,  flood hazard area or  designated  wetlands
area.  Except as set forth on  Schedule  4.10(a),  neither  the  Seller  nor the
Shareholder  has received any written  notice of, and neither the Seller nor the
Shareholder has Knowledge of, any assessments  for public  improvements  against
the  Real  Estate  or any  written  order  by any  Governmental  Authority,  any
insurance  company  which has issued to the Seller or the  Shareholder  a policy
with respect to any parcel of Real Estate or any board of fire  underwriters  or
other body exercising similar functions that: (i) relates to material violations
of  building,  safety or fire  ordinances  or  regulations  which  have not been
remediated;  (ii) claims any material  defect or deficiency  with respect to any
parcel of Real  Estate  which has not been  remediated;  or (iii)  requests  the
performance  of any  repairs,  alterations  or other work to or in any parcel of
Real  Estate  or in the  streets  bounding  the  same  that  have  not yet  been
performed. Neither the Seller nor the Shareholder has made any arrangements with
any  Governmental  Authority  for the deferral of taxes or  assessments  for any
parcel of Real Estate. To the Knowledge of the Seller and the Shareholder, there
is  no  condemnation,   expropriation,  eminent  domain  or  similar  proceeding
affecting all or any portion of the Real Estate  pending or  threatened.  Except
where the Seller is lessee,  to the Knowledge of the Seller and the Shareholder,
there  are no  leases,  subleases,  licenses,  concessions  or other  agreements
(written or oral)  granting to any Person the right to use or occupy any portion
of each parcel of Real Estate.  Except as set forth on Schedule 4.10(a),  to the
Knowledge of the Seller and the Shareholder, there are no outstanding options or
rights of first  refusal to  purchase  any parcel of Real  Estate or any portion
thereof or interest therein.

            4.11  Personal  Property.  Schedule  4.11  sets  forth  all items of
personal  property  of the Seller  which have a book value or current  estimated
market value in excess of $25,000. Except for such personal property as has been
disposed of in the Ordinary  Course of Business  since the Latest  Balance Sheet
Date, the Seller owns all property  reflected on the Latest  Balance Sheet,  and
will own all  property  reflected  on the Closing  Balance  Sheet.  All tangible
personal  property of the Seller is located upon the Seller's  premises,  except
items in transit  or as set forth on  Schedule  4.11.  To the  Knowledge  of the
Seller and the  Shareholder,  all such property set forth on Schedule 4.11 is in
good condition and repair (normal wear and tear excepted).

            4.12 All Necessary  Assets.  The Purchased Assets  constitute all of
the material assets which are used in, and all of the assets which are necessary
for,  the conduct of the  Business,  as  presently  conducted  and  presently is
proposed to be conducted, subject to Section 1.5.

            4.13  Receivables.  All of the  Receivables (a) have arisen and will
arise solely from bona fide  transactions in the Ordinary Course of Business and
are not and will not be subject to  


                                      -12-


<PAGE>

counterclaim  or set-off and are not or will not be otherwise in dispute and (b)
are, and as of the Closing Date will, be good and collectible in full (less only
the  allowance  for  doubtful  accounts  receivable  as set forth on the  Latest
Balance Sheet), and will be collected (less only such allowance) within 120 days
following the Closing Date. Schedule 4.13 contains a true and correct aging list
of Receivables as of March 18, 1999, specifying the date of original invoice and
current payment status of each Receivable.

            4.14 Inventories.  The Inventories of the Seller have been valued at
the lower of cost or market.  The values at which  Inventories  are reflected on
the Financial Statements have been determined on a  first-in-first-out  basis in
accordance with GAAP consistently applied for all periods. The Inventories which
consist of  work-in-process  are being  completed  on schedule  and there are no
forfeitures, chargebacks or penalties which have been or will be incurred due to
the failure of the Seller to complete the  work-in-progress  in a timely manner.
None of the  Inventories  have been  consigned to others,  nor is any  inventory
consigned to the Seller.  All of the Inventories are located at San Luis Obispo,
California.

             4.15 Intellectual Property.

            (a) The Seller  owns or has the right to use  pursuant  to  license,
sublicense, agreement, or permission all Intellectual Property necessary for the
operation of the Businesses. Each item of Intellectual Property owned or used by
the Seller immediately prior to the Closing hereunder which constitute Purchased
Assets will be owned or available  for use by the Buyer on  identical  terms and
conditions immediately subsequent to the Closing hereunder.  To the Knowledge of
the Seller and the  Shareholder,  the Seller has taken all  necessary  action to
maintain and to protect each item of Intellectual  Property that it owns or uses
which constitute Purchased Assets, including, but not limited to, payment of any
and all maintenance fees and annuities.

            (b)  The   Seller  has  not   interfered   with,   infringed   upon,
misappropriated,  or otherwise come into conflict with any Intellectual Property
of any  Person  and,  except  as set  forth on  Schedule  4.15(b),  neither  the
Shareholder nor the Seller has received any charge, complaint, claim, demand, or
notice  alleging  any  such  interference,  infringement,  misappropriation,  or
violation of any Intellectual  Property of any other party,  including,  but not
limited  to, any claim that the Seller  must  license or refrain  from using any
Intellectual Property of any third party.

            (c) Schedule  4.15(c)  identifies each patent or registration  which
has been issued to the Seller with respect to any of its Intellectual  Property,
identifies each pending patent application or application for registration which
the  Seller  has made with  respect  to any of its  Intellectual  Property,  and
identifies each license,  agreement,  or other  permission  which the Seller has
granted to any third  party with  respect  to any of its  Intellectual  Property
(together  with any  exceptions).  The Seller has delivered to the Buyer correct
and complete copies of all such patents, registrations,  applications, licenses,
agreements,  and  permissions (as amended to date) and has made available to the
Buyer correct and complete copies of all other written documentation  evidencing
ownership and prosecution (if  applicable) of each such item.  Schedule  4.15(c)
identifies  each  trade  name or  unregistered  trademark  used by the Seller in
connection with any of its businesses. With respect to each item of Intellectual
Property required to be identified in Schedule 4.15(c):


                                      -13-


<PAGE>

                     (i) the Seller  possesses all right,  title and interest in
              and to the item,  free and clear of any  Lien,  license,  or other
              restriction;

                     (ii) the item is not subject to any outstanding injunction,
              judgment, order, decree, ruling, or charge;

                     (iii) no action, suit, proceeding,  hearing, investigation,
              claim, or demand is pending or, to the Knowledge of the Seller and
              the  Shareholder,  is threatened  which  challenges  the legality,
              validity, enforceability, use, or ownership of the item; and

                     (iv) the  Seller  has not  entered  into any  agreement  to
              indemnify   any   Person   for  or   against   any   interference,
              infringement, misappropriation, reexamination, opposition or other
              conflict with respect to the item.

             (d) Schedule  4.15(d)  identifies  each and every  material item of
Intellectual Property (excluding  commercially available computer software) that
any third party owns or licenses  and that the Seller uses  pursuant to license,
sublicense,  agreement,  or  permission.  The Seller has  delivered to the Buyer
correct and complete copies of all such licenses,  sublicenses,  agreements, and
permissions  (as  amended to date).  With  respect to each item of  Intellectual
Property  required to be  identified  in Schedule  4.15(d),  except as stated in
Schedule 4.15(d):

                     (i)  the  license,  sublicense,  agreement,  or  permission
              covering the item is legal, valid,  binding,  enforceable,  and in
              full force and effect;

                     (ii) the license, sublicense, agreement, or permission will
              continue to be legal,  valid,  binding,  enforceable,  and in full
              force and effect on identical terms following the  consummation of
              the transactions  contemplated  hereby  (including the assignments
              and assumptions referred to in Section 1.2 above);

                     (iii) to the  Knowledge of the Seller and the  Shareholder,
              no party to the license,  sublicense,  agreement, or permission is
              in breach or default,  and no event has occurred which with notice
              or lapse of time  would  constitute  a breach or default or permit
              termination, modification, or acceleration thereunder;

                     (iv) no party to the  license,  sublicense,  agreement,  or
              permission has repudiated any provision thereof;

                     (v) to the  Knowledge  of the Seller  and the  Shareholder,
              with  respect  to  each  sublicense,   the   representations   and
              warranties  set forth in  subsections  (i) through  (iv) above are
              true and correct with respect to the underlying license;

                     (vi) the underlying  item of  Intellectual  Property is not
              subject to any outstanding  injunction,  judgment,  order, decree,
              ruling or charge;

                     (vii) no action, suit, proceeding,  hearing, investigation,
              claim, or demand is pending or, to the Knowledge of the Seller and
              the  Shareholder,  is threatened  which  


                                      -14-


<PAGE>

              challenges  the  legality,  validity,  or  enforceability  of  the
              underlying item of Intellectual Property; and

                     (viii) the  Seller  has never  granted  any  sublicense  or
              similar right with respect to the license, sublicense,  agreement,
              or permission.

            (e) Except as set forth on Schedule 4.15(e),  neither the Seller nor
the Shareholder have any Knowledge of any products,  inventions or procedures of
competitors  which  reasonably  could  or  do  infringe  or  misappropriate  any
Intellectual Property of the Seller. The Seller has not given formal or informal
notice of infringement or sent a demand to "cease and desist" to any Person.

             4.16 Insurance.

            (a) General.  Schedule  4.16(a) lists and contains a description  of
each policy of  insurance  owned by the Seller  currently  in effect  (including
without  limitation,   policies  for  fire  and  casualty,  liability,  worker's
compensation,  business  interruption,  umbrella coverage,  products  liability,
medical, disability and other forms of insurance) specifying the insurer, amount
of coverage, type of insurance, policy number, deductible limits and any pending
claim  in  excess  of  $5,000,   whether  or  not  covered  by  insurance   (the
"Insurance").  True and complete  copies of each policy of  Insurance  have been
previously  delivered to Buyer.  The Insurance is in full force and effect,  all
premiums with respect thereto  covering all periods up to and including the date
hereof have been paid, and no notice of  cancellation  or  termination  has been
received by the Seller with respect to any such policy.  To the Knowledge of the
Seller and the Shareholder,  the Insurance is sufficient for compliance with all
requirements of law and with all agreements to which the Seller is a party.  The
Seller has not  received any notice from or on behalf of any  insurance  carrier
issuing  any  such  policy  that:   (i)  insurance   rates  will   hereafter  be
substantially  increased;  (ii) that there will  hereafter  be no renewal of any
such  policy;  or (iii) that  alteration  of any  personal  or real  property or
purchase  of  additional  equipment,  or  modification  of any  method  of doing
business, is required or suggested.

            (b)  Denials  of  Coverage.  The  Seller  has not been  refused  any
insurance  with  respect  to the  Seller's  assets  or  operations,  nor has the
Seller's  coverage been limited by any insurance carrier to which it has applied
for or with which it has carried insurance.

            (c)  Claims.  Schedule  4.16(c)  sets forth a list of and summary of
information  pertaining to, all claims (other than workers' compensation claims)
of property  damage and  personal  injury or death  against the Seller which are
currently  pending or were made during the  preceding  three (3) fiscal years or
the current fiscal year.  Except as set forth on Schedule  4.16(c),  all of such
claims are fully  satisfied or are being  defended by an  insurance  carrier and
involve no exposure to the Seller (other than deductibles).

            (d)  Self-Insurance.  Schedule 4.16(d) describes any  self-insurance
programs relating to the Business.

            4.17 Permits.  The Seller possesses all Permits (including,  without
limitation,  occupancy  permits for real estate and permits required pursuant to
Environmental  Law) as are necessary for the  


                                      -15-


<PAGE>

consummation  of the  transactions  contemplated  hereby or the  conduct  of its
business or operations,  except where the failure to hold such Permits would not
have a Material Adverse Effect on the Business.  Schedule 4.17 sets forth a list
of all Permits and true and complete copies of each written document  evidencing
or affecting any Permits have been previously delivered to the Buyer. The Seller
is in compliance with the terms and conditions of all Permits, except where such
noncompliance would not result in a Material Adverse Effect.

             4.18 Material Contract. Schedule 4.18 lists the following contracts
and other agreements to which the Seller is a party:

             (a) Leases. All leases of real or personal property,  excluding the
leases described in Schedule 4.10(a) hereof;

             (b)  Purchase  and Sale  Orders.  All written and oral  agreements,
including  purchase  orders,  relating  to the  purchase  or sale  of  products,
services or supplies by the Seller other than (i) any such agreements which have
been completely performed and (ii) individual purchase or sales orders issued in
the  Ordinary  Course  of  Business  for  amounts  in each case not in excess of
$10,000 individually;

             (c) Certain  Agreements.  All of the following  described  types of
agreements or documents:  (i)  distributorship,  sales representative or similar
agreements;  (ii)  license,  royalty or  similar  agreements;  (iii)  service or
maintenance;  (iv) protective services or security;  and (v) commission or other
contingent agreements pursuant to which the Seller's obligation to make payments
is in excess of $10,000 per year,  or pursuant to which the Seller's  obligation
to make contingent payments is dependent upon sales,  revenues,  income, success
or other performance standard;

             (d)  Other  Financial  Obligations.  All  other  written  and  oral
agreements or commitment  which requires the Seller to pay or expend,  after the
Closing,  more than $10,000 in the aggregate of all such instances with the same
or related parties;

             (e)  Capital   Expenditures.   All  outstanding  written  and  oral
commitments  by the Seller to make a capital  expenditure,  capital  addition or
capital improvement in excess of $10,000;

             (f) Employment Contracts.  All written and oral employment,  bonus,
incentive  compensation,  profit sharing,  stock option,  salary-continuation or
other fringe benefit agreements, other than those disclosed in Schedule 4.25(a),
currently in effect or to become  effective,  or under which any amounts  remain
unpaid,  on the date of this Agreement or to become  payable or effective  after
the date of this Agreement;

             (g)  Non-Compete  Covenants.  All written and oral covenants not to
compete, non-solicitation covenants and non-disclosure covenants in favor of the
Seller, or binding upon or against the Seller;

             (h) Discounts. All agreements, arrangements or programs pursuant to
which the Seller has offered,  promised or made  available to its  customers any
volume discount, rebate, credit or allowance; and


                                      -16-


<PAGE>

            (i) Non-Ordinary Course Agreements. All other contracts,  agreements
and  arrangements  binding  upon the Seller  and which was made or entered  into
either other than in the Ordinary Course of Business or the performance of which
involves consideration in excess of $10,000.

The  Seller  has  delivered  to the Buyer a correct  and  complete  copy of each
written  agreement  listed on  Schedule  4.18 (as amended to date) and a written
summary  setting forth the material  terms and conditions of each oral agreement
which involve amounts in excess of $10,000 as referred to in Schedule 4.18. With
respect to each such  agreement:  (i) the  agreement is legal,  valid,  binding,
enforceable,  except  as  enforceability  may  be  limited  by  (A)  bankruptcy,
insolvency,  reorganization,  moratorium  or similar  law  affecting  creditors'
rights generally or (B) general  principles of equity,  whether  considered in a
proceeding in equity or at law, and in full force and effect;  and (ii) no party
is in breach or default, and no event has occurred which with notice or lapse of
time would constitute a breach or default, or permit  termination,  modification
or  acceleration  under the  agreement;  and (iii) no party has  repudiated  any
provision of the agreement.

            4.19  Litigation.  Except as set forth on Schedule  4.19 or Schedule
4.21(a),  there is not now,  and there has not been  within  the last  three (3)
years, any litigation,  claim,  proceeding or investigation  pending, or, to the
Seller's or the Shareholder's  Knowledge,  threatened against or relating to the
Seller,  its  properties  or  the  Business,  or  the  ability  to  perform  its
obligations under this Agreement. Schedule 4.19 sets forth, with respect to each
item  described  thereon,  the name or  title  of the  action  (and  parties  or
potential parties thereto),  a description of the nature of the action or claim,
and an  estimate  of the  maximum  liability  of the  Seller  in the event of an
adverse result.  Except as so described,  neither the Seller nor the Shareholder
have Knowledge of any facts or circumstances  which reasonably could be expected
to ripen into  litigation,  proceeding or  investigation  that would result in a
Material  Adverse  Effect.  Except as  described on Schedule  4.19,  there is no
outstanding order, decree or stipulation issued by any Governmental Authority to
which  the  Seller is a party or  subject  and which  adversely  affects  or may
adversely affect its properties, business or prospects.

            4.20 Compliance  With Law. Except as set forth on Schedule  4.21(a),
the  conduct  of the  Business  does not  violate,  nor is the Seller in default
under, any law, statute,  ordinance,  rule, regulation,  code, license,  permit,
guideline,  order,  arbitration  award,  judgment or decree,  and Buyer will not
after the Closing  incur any  Liability  or  obligation  as a result of any such
violation or default  existing at the Closing or arising or accruing  thereafter
but based upon conditions  existing at the Closing,  except where such violation
or default would not have a Material  Adverse Effect on the Business.  Except as
set forth on Schedule 4.20, no material  expenditures are anticipated  which are
necessary or appropriate for the continuation of the Business in compliance with
any such law, statute,  rule,  regulation,  code, license,  permit,  guidelines,
order, arbitration award, judgment or decree.

             4.21 Environmental Matters.

             (a)  Environmental  Compliance.  Except  as set  forth in  Schedule
4.21(a),   (i)  the  Seller  is  


                                      -17-


<PAGE>

in  material  compliance  with  all  applicable  Environmental  Laws  and to the
Knowledge of the Seller and the Shareholder,  the Leased Property is in material
compliance with all applicable Environmental Laws; (ii) the Seller has furnished
or made available to the Buyer and Promega all communications (either written or
oral) received by the Seller or the Shareholder from a Governmental Authority or
other  Person  which  alleges  that the Seller,  the  Shareholder  or the Leased
Property is not in material  compliance with any applicable  Environmental  Law;
(iii) to the Knowledge of the Seller and the Shareholder, neither the Seller nor
the Shareholder is under  investigation  by any  Governmental  Authority for the
failure to comply in all material  respects  with any  Environmental  Law;  (iv)
neither  the Seller nor the  Shareholder  is  required  to take on behalf of the
Business  or at the  Real  Estate,  any  Remedial  Action  by  any  Governmental
Authority or  Environmental  Law; and (v) to the Knowledge of the Seller and the
Shareholder,  neither the Seller nor the  Shareholder  has made any  statements,
warranties,  or representations  in any documents  submitted to any Governmental
Authority  or  submittal   created   pursuant  to  an   obligation   imposed  by
Environmental  Law containing any untrue  statement of material fact or omitting
any statement of material fact which render the  statements  made  misleading in
connection with any Environmental Law.

            (b)  Environmental  Permits.  The  Seller and the  Shareholder  have
obtained all Environmental  Permits necessary for the Seller's operations on the
Leased Property, and all such Environmental Permits are in good standing.

            (c) Pending Litigation.  Except as set forth in Schedule 4.21(c), to
the Knowledge of the Seller and the Shareholder, there is no Environmental Claim
pending or threatened  against the Seller or the  Shareholder in connection with
the Leased  Property  or the  Business,  operations  or  actions of the  Seller.
Neither  the Seller nor the  Shareholder  has  received  any notice of any past,
present or future event, condition, circumstance,  activity, practice, incident,
action  or plan  which  may give  rise to any  Environmental  Claim  based on or
related to the Leased Property.

            (d) Disposal Practices.  Except as set forth in Schedule 4.21(d), to
the  Knowledge  of the Seller  and the  Shareholder,  neither  the  Seller,  the
Shareholder  nor any other Person has arranged  for the  disposal,  treatment or
recycling  of, or  transported  for  disposal,  treatment  or  recycling  of any
Environmental  Material,  including,  but not limited to, any  Hazardous  Waste,
PCB-containing  Material,  petroleum  substance  (including  crude  oil  or  any
fraction  thereof),  or petroleum  product from the Leased Property to any other
location which has been identified on the National Priority List (NPL),  CERCLIS
or state  equivalent  lists. To the knowledge of the Seller and the Shareholder,
no  Environmental  Materials  have, in a manner that violates any  Environmental
Laws, been transported from the Leased Property for purposes of disposal.

            4.22  Contingent  and  Undisclosed  Liabilities.  The  Seller has no
Liabilities,  whether  such  Liabilities  are now  known  or  unknown,  fixed or
contingent,  of any nature  whatsoever,  except:  (i) those fully  reflected  or
reserved  against on the face of the Latest  Balance  Sheet  (rather than in any
notes  thereto);  (ii) those fully disclosed in this Agreement and the Schedules
hereto; or (iii) Liabilities which do not result in a Material Adverse Effect.


                                      -18-


<PAGE>

             4.23 Tax Matters.

            (a) The Seller has filed all Tax  Returns  that it was  required  to
file. All such Tax Returns were correct and complete in all respects.  All Taxes
owed by the Seller  (whether or not shown on any Tax Return) have been paid. The
Seller is not currently the beneficiary of any extension of time within which to
file  any  Tax  Return.  No  claim  has  ever  been  made by an  authority  in a
jurisdiction  where the Seller  does not file Tax  Returns  that it is or may be
subject  to  taxation  by that  jurisdiction.  There  are no Liens on any of the
assets of the Seller  that arose in  connection  with any  failure  (or  alleged
failure) to pay any Tax.

            (b) The Seller has withheld and paid all Taxes required to have been
withheld and paid in  connection  with  amounts  paid or owing to any  employee,
creditor, stockholder, or other third party.

             4.24 Employees; Labor Matters.

             (a) Schedule 4.24(a) lists each of the following:

              (i)    (A) all officers and directors of the Seller; (B) the names
                     and current  annual  salary rates (and bonus,  incentive or
                     commission  arrangements)  of all  full-time  and part-time
                     employees  and agents of the Seller;  (C) all loans made by
                     the Seller to its  employees  and a statement  of the terms
                     thereof;  and (D) a list of all of the  Seller's  employees
                     who are  currently  laid-off or on parental,  disability or
                     other leave; and

              (ii)   All employees who are expected,  as of the Closing Date, to
                     have earned but unused vacation and other personal days (or
                     earned but unpaid  vacation pay in lieu thereof),  together
                     with an estimate of the dollar amount thereof.

             (b)  The  Seller  is  not a  party  to  any  collective  bargaining
agreement  or  bound  to any  other  agreement  with a labor  union.  The  labor
relations of the Seller are  satisfactory  in that there has not been within the
preceding  three (3) fiscal years of the Seller and the current fiscal year, nor
is there currently,  any strike, walkout or work stoppage;  nor, to the Seller's
and the  Shareholder's  Knowledge,  is any such action  threatened.  Neither the
Seller nor the  Shareholder  has been  notified of any  proceedings  pending for
certification or  representation  before the National Labor Relations Board nor,
to the  Seller's  and the  Shareholder's  Knowledge,  has there been any attempt
within  the  preceding  three (3) fiscal  years or the  current  fiscal  year to
organize the employees of the Seller into a collective  bargaining  unit. To the
Knowledge of the Seller and the Shareholder,  there is no investigation pending,
nor is there any uncorrected or unresolved citation, complaint or charge issued,
by any agency  responsible for administering or enforcing laws relating to labor
relations,  employee safety or health, fair labor standards and equal employment
opportunity nor, to the Knowledge of the Seller and the Shareholder, is any such
proceeding threatened.


                                      -19-


<PAGE>

             4.25 Employee Benefit Plans.

            (a) General.  Schedule  4.25(a) sets forth a true and complete  list
and brief  description  of each "employee  pension  benefit plan" (as defined in
Section 3(2) of ERISA),  each  "employee  welfare  benefit  plan" (as defined in
Section 3(1) of ERISA) and each and every other employee benefit plan maintained
or  contributed  to, or  required  to be  contributed  to, by the Seller for the
benefit of any officers or employees,  current or former, active or inactive, of
the  Business,  whether on an active or frozen  basis (all the  foregoing  being
herein  called  "Benefit  Plans").  The Seller  does not have any formal plan or
commitment,  whether  legally  binding or not, to modify or change any  existing
Benefit Plan that would  affect any  employee or former  employee of the Seller.
True,  complete  and  correct  copies  of the  following  have  been  previously
delivered to the Buyer: (i) each Benefit Plan, including any amendments thereto;
(ii) the most recent Form 5500 or Form 5500-C filed with the IRS with respect to
each  Benefit  Plan (if any such  report was  required),  (iii) the most  recent
summary  plan  description  together  with each  subsequent  summary of material
modifications  required under ERISA with respect to each Benefit Plan; (iv) each
trust agreement or other funding arrangement relating to each Benefit Plan which
is an  employee  pension  benefit  plan as  defined  in  Section  3(2) of  ERISA
(hereinafter  "Pension  Plan");  and (v) all currently  effective IRS rulings or
determination letters relating to each Pension Plan.

            (b) PBGC.  No Pension Plan is subject to Title IV of ERISA and there
are no facts which might give rise to any liability of the Seller under Title IV
of ERISA or which could  reasonably be anticipated to result in any claims being
made against the Seller by the Pension Benefit Guaranty Corporation with respect
to any Pension Plan. For purposes of the preceding  sentence and Section 4.25(e)
hereof,  the term  "Seller"  shall also include any entity which is under common
control or affiliated with the Seller,  within the meaning of Section 4001(b)(1)
of ERISA, and the rules and regulations  promulgated  thereunder and/or Sections
414(b),  (c), (m) or (o) of the Code, and the rules and regulations  promulgated
thereunder.

            (c) Post-Retirement  Benefits.  Except as disclosed on Schedule 4.18
or Schedule  4.25(a),  no Benefit  Plan  provides  benefits,  including  without
limitation,  death,  disability,  or medical benefits  (whether or not insured),
with  respect  to current  or former  employees  of the  Business  beyond  their
retirement or other  termination of service other than (i) coverage  mandated by
applicable law, or (ii) death benefits or retirement  benefits under any Pension
Plan.

            (d) COBRA.  Each "group  health plan" (within the meaning of Section
5000(b)(1)  of the Code)  maintained  by the Seller  that  covers or has covered
employees of the Business,  as of the first day of each such group health plan's
first plan year  beginning on or after July 1, 1986,  has been  administered  in
compliance with the continuation  coverage  requirements  initially enacted as a
part of the Consolidated Omnibus Budget Reconciliation Act of 1985 ("COBRA") and
as formerly provided under Section 162(k) of the Code and as currently  provided
under  Sections  601 through 609 of ERISA and Section  4980B of the Code and any
regulations  promulgated or proposed under any of those Code or ERISA  sections,
except where a failure to  administer  any such group health plan in  compliance
with such laws and regulations would not have a Material Adverse Effect.

            (e) Multiemployer  Plans. At no time has the Seller been required to
contribute  to, or  incurred  any  withdrawal  liability  (within the meaning of
Section  4201 of ERISA) to any  Benefit  


                                      -20-


<PAGE>

Plan which is a  multiemployer  plan as defined in Section 3(37) of ERISA and no
event has  occurred  that  could  result in any  liability  of the Seller to any
multiemployer plan.

            (f) Foreign Employees.  No current officers or employees,  active or
inactive,  of the  Business  regularly  work at a  location  outside  the United
States.

            (g)  Family and  Medical  Leave.  Except as  disclosed  on  Schedule
4.25(g), on the date hereof, no employees of the Seller are inactive or are on a
leave of  absence  covered by the Family  and  Medical  Leave Act of 1993,  P.L.
103-3.

            4.26  Products  Liability.  To the  Knowledge  of the Seller and the
Shareholder,  there exists no defect in the design or  manufacture of any of the
Seller's products and there is no pending or threatened action,  suit,  inquiry,
proceeding  or  investigation  by or before any Person  relating  to any product
alleged to have been manufactured,  distributed or sold by the Seller to others,
and alleged to have been defective or improperly  designed or manufactured or in
breach of any express or implied product warranty ("Products Liability").  There
exists  no  pending  or, to the  Knowledge  of the  Seller  or the  Shareholder,
threatened,  Products  Liability  claims. To the Knowledge of the Seller and the
Shareholder,  there  is no  valid  basis  for any such  suit,  inquiry,  action,
proceeding,  investigation or claim. The Seller does not have any Liability (and
there is no basis for any present or future action, suit,  proceeding,  hearing,
investigation,  charge,  complaint,  claim, or demand against any of them giving
rise to any Liability) arising out of any injury to individuals or property as a
result of the ownership,  possession, or use of any product manufactured,  sold,
leased or delivered by the Seller.  The Seller is insured,  and has been insured
continuously for the past five years against product liabilities,  in accordance
with  the  insurance  policies  identified  on  Schedule  4.16(a)  (including  a
statement  of the  name of the  insurer,  the type of  policy,  the  amounts  of
coverage and the applicable deductible limits).

            4.27 Product Warranty. All product warranties given by the Seller in
connection  with the  Business:  (a)  limit the  remedy  available  to  Seller's
customers to the replacement of the warranted goods by Seller, or alternatively,
a refund of the sales price of such goods to customer;  (b)  expressly  disallow
claims for incidental or consequential  damages;  and (c) expressly disclaim all
other  warranties  not expressly  stated  therein,  whether  express or implied,
including warranties of merchantability, fitness for a particular purpose.

            4.28 Events  Subsequent  to Latest  Fiscal  Year End.  Except as set
forth on  Schedule  4.28,  since the  Latest  Fiscal  Year End,  the  Seller has
operated in the Ordinary  Course of Business and there has not been any Material
Adverse  Effect.  Without  limiting the generality of the foregoing,  since that
date, except as set forth on Schedule 4.28:

            (a) The Seller has not sold, leased, transferred, or assigned any of
its  assets,  tangible  or  intangible,  other  than sales of  Inventory  in the
Ordinary  Course of  Business  or which  would not result in a Material  Adverse
Effect on the Business;

            (b) The Seller has not entered into any agreement,  contract,  lease
or license (or series of related  agreements,  contracts,  leases, and licenses)
either involving more than $10,000 or outside the Ordinary Course of Business;


                                      -21-


<PAGE>

            (c) No party  (including  the Seller) has  accelerated,  terminated,
modified, or cancelled any agreement,  contract, lease, or license (or series of
related agreements,  contracts, leases, or licenses) involving more than $10,000
individually to which the Seller is a party or by which it is bound;

            (d) The Seller has not made any  capital  expenditure  (or series of
related capital expenditures) either involving more than $25,000 individually or
outside the Ordinary Course of Business;

            (e) The Seller has not made any capital  investment in, any loan to,
or any  acquisition  of the securities or assets of, any other Person (or series
of related capital  investments,  loans, and acquisitions) either involving more
than $25,000 individually or outside the Ordinary Course of Business;

            (f) The Seller has not issued any note, bond, or other debt security
or created, incurred, assumed, or guaranteed any indebtedness for borrowed money
or capitalized lease obligation;

            (g) The Seller has not delayed or postponed  the payment of accounts
payable and other Liabilities outside the Ordinary Course of Business;

            (h) The Seller has not cancelled,  compromised,  waived, or released
any right or claim (or series of related rights and claims);

            (i) The Seller has not  granted  any  license or  sublicense  of any
rights under or with respect to any of its Intellectual Property;

            (j) There has been no change made or authorized  in the  certificate
of incorporation or bylaws of the Seller;

            (k) The Seller has not issued, sold, or otherwise disposed of any of
its capital stock, or granted any options, warrants, or other rights to purchase
or obtain (including upon conversion,  exchange, or exercise) any of its capital
stock;

            (l) The Seller has not declared,  set aside, or paid any dividend or
made any  distribution  with respect to its capital stock (whether in cash or in
kind) or redeemed, purchased, or otherwise acquired any of its capital stock;

            (m) The Seller has not experienced any damage,  destruction, or loss
(whether  or not  covered by  insurance)  to its  property,  other than  damage,
destruction  or loss  that did not,  individually  or in the  aggregate,  have a
Material Adverse Effect;

            (n) The Seller  has not made any loan to, or entered  into any other
transaction with, any of its directors,  officers, and employees, except for the
payment of compensation in the Ordinary Course of Business;


                                      -22-


<PAGE>

            (o) The Seller  has not  entered  into any  employment  contract  or
collective bargaining  agreement,  written or oral, or modified the terms of any
existing such contract or agreement outside the Ordinary Course of Business;

            (p) The Seller has not granted any increase in the base compensation
of any of its directors,  officers, and employees outside the Ordinary Course of
Business;

            (q) The Seller has not adopted, amended, modified, or terminated any
bonus,  profit-sharing,  incentive,  severance,  or  other  plan,  contract,  or
commitment for the benefit of any of its directors,  officers, and employees (or
taken any such action with respect to any other Employee  Benefit  Plan),  other
than as necessary to comply with applicable law (including Section 401(a) of the
Code) and other than in the Ordinary Course of Business;

            (r) The Seller has not made or  pledged  to make any  charitable  or
other capital contribution outside the Ordinary Course of Business;

            (s) Neither  the Seller nor the  Shareholder  has  entered  into any
agreement or arrangement for the sale of the Business or any part thereof or for
the purchase of another business, whether by merger, consolidation,  exchange of
capital stock or otherwise (other than with respect to this Agreement);

            (t) The Seller has not changed or modified its accounting methods or
practice;

            (u) The Seller has not settled, or agreed to settle, any litigation,
arbitration or other proceeding; and

            (v) The Seller has not committed to any of the foregoing.

            4.29  Customers and  Suppliers.  Schedule 4.29 lists,  in descending
order,  those customers of the Seller accounting for at least 5% of annual sales
volume in the  Seller's  most  recently  completed  fiscal  year and the top ten
suppliers of raw materials or supplies accounting for the largest annual expense
to the  Seller.  The Seller  has  received  no notice,  nor do the Seller or the
Shareholder  have  any  Knowledge,  that  (a) any  customer  of the  Seller  who
accounted  for  five  percent  (5%) or more of the  Seller's  sales  during  its
immediately  preceding  fiscal  year or (b) any  supplier to the Seller (if such
supplier could not be replaced by the Seller with no material  adverse effect to
it), has terminated or will terminate business relations with the Seller.

            4.30  Brokerage.  Except as described on Schedule 4.30,  neither the
Seller nor the Shareholder has incurred, or made commitments for, any brokerage,
finders' or similar fee in connection with the transactions contemplated by this
Agreement.

            4.31 Affiliate  Transactions.  Except as described on Schedule 4.31,
the Seller:  (a) has not had any financial  transactions or arrangements  (other
than  payment  of  regular  salary to  Affiliates  who are  employees)  with any
Affiliate  since the Latest  Fiscal Year End, and (b) does not have and will not
have any  present  or  future  obligation  to  enter  into  any  transaction  or
arrangement  with any  Affiliate.  Except as  described  on  Schedule  4.31,  no
Affiliate owns,  directly or indirectly,  or is a 


                                      -24-


<PAGE>

director,  member,  officer or  employee  of, or  consultant  to,  any  business
organization  which is a competitor,  supplier,  or customer of the Seller,  nor
does any Affiliate own any assets or properties which are used in the Business.

            4.32  Guaranties.  The Seller is not a guarantor or otherwise liable
for any Liability  (including,  without  limitation,  indebtedness) of any other
Person.

            4.33  Investment.  The Seller (i) understands  that the Note has not
been, and will not be,  registered  under the Securities Act, or under any state
securities  laws,  and are being  offered and sold in reliance  upon federal and
state exemptions for  transactions  not involving any public  offering,  (ii) is
acquiring the Note solely for its own account for investment  purposes,  and not
with a view to the distribution thereof (except to the Shareholder),  (iii) is a
sophisticated  investor with  knowledge and experience in business and financial
matters, (iv) has received certain information  concerning the Buyer and has had
the opportunity to obtain additional information as desired in order to evaluate
the merits and the risks  inherent in holding the Note,  (v) is able to bear the
economic risk and lack of liquidity  inherent in holding the Note and (vi) is an
Accredited Investor.

            4.34  Commission  Filings.   The  Shareholder  has  filed  with  the
Commission  all reports,  registration  statements,  proxy  statements and other
filings  (including  all notes,  exhibits and  schedules  thereto and  documents
incorporated by reference  therein) required to be filed by the Shareholder with
the Commission since December 31, 1997 (such reports,  registration,  statements
and  other  filings,   together  with  any  amendments  thereto,  are  sometimes
collectively  referred to as the  "Commission  Filings").  The  Shareholder  has
delivered to the Buyer true and complete copies of all Commission Filings within
the past year. The Commission Filings and any forms, reports and other documents
filed by the  Shareholder  with the Commission  after the date of this Agreement
(a) were or will be prepared in all  material  respects in  accordance  with the
requirements of the Securities Act and the Exchange Act, as the case may be, and
(b) at the time they were or will be filed with the Commission,  did not contain
any  untrue  statement  of a  material  fact or omit to  state a  material  fact
required to be stated therein or necessary to make the statements  made therein,
in light of the  circumstances  under which they were made, not misleading.  The
Seller has not ever been  required  to file any form,  report or other  document
with the Commission.  Each of the audited consolidated  financial statements and
unaudited  interim  financial   statements   (including  any  related  notes  or
schedules)  included in the Commission  Filings was prepared in accordance  with
GAAP applied on a consistent basis except as may be indicated  therein or in the
notes or schedules  thereto,  and fairly presents the financial  position of the
Shareholder  and its  consolidated  subsidiaries as at the dates thereof and the
results of their  operations,  cash flows,  changes in  financial  position  and
changes in stockholders' equity for the periods then ended.

            4.35 Amersham  Termination.  Neither the Seller nor the  Shareholder
has received any notices or other  communication  from  Amersham  International,
p.l.c.  challenging  the  validity of the Seller's  termination  of that certain
agreement  dated August 16, 1995 between the Seller and Amersham  International,
p.l.c.

            4.36   Representations   and  Warranties   True  and  Correct.   The
representations  and warranties  contained herein, and, subject to the following
sentence,  all other  documents,  certifications,  materials  and  statements or
information  given to the Buyer by or on behalf of the 


                                      -24-


<PAGE>

Seller or Shareholder or disclosed in this Agreement,  do not include any untrue
statement  of a material  fact or omit to state a material  fact  required to be
stated herein or therein in order to make the statements  herein or therein,  in
light  of  the  circumstances   under  which  they  are  made,  not  misleading.
Notwithstanding the foregoing,  neither the Seller nor the Shareholder makes any
representation,   warranty  or  other   assurance  that  any  of  the  financial
information,  financial  estimates,  forecasts or projections  contained in that
certain Confidential  Memorandum,  delivered to Promega via facsimile on October
28, 1998 and relating to the Business, will be realized.

                                    ARTICLE V

                          REPRESENTATIONS OF THE BUYER

            In order to induce the Seller and the Shareholder to enter into this
Agreement,  the Buyer makes the following  representations and warranties to the
Seller and the Shareholder (which  representations  and warranties shall survive
the  Closing to the extent  provided  in Section  11.4),  each of which shall be
deemed to be  independently  material  and  relied  upon by the  Seller  and the
Shareholder,  regardless of any investigation  made by, or information known to,
the Seller and the Shareholder.

            5.1 Ownership, Organization and Qualification. Each of the Buyer and
Promega is a corporation  duly  incorporated and validly existing under the laws
of the State of Wisconsin,  has filed with the appropriate state agency the most
recent  annual  report  required  to be filed by it, has not filed  articles  of
dissolution  and has a  perpetual  period  of  existence.  Each of the Buyer and
Promega are  qualified  to transact  business  as a foreign  corporation  in the
jurisdictions where it is required to be so qualified,  except where the failure
to be qualified would not result in a material adverse effect on the operations,
prospects or condition (financial or otherwise) on Promega.

            5.2  Authorization.  Each of the Buyer and Promega  (with respect to
its  obligations  under Section  12.2) has all necessary  power and authority to
enter into and perform the transactions  contemplated  hereby in accordance with
the terms and conditions  hereof.  The execution and delivery of this Agreement,
and the  performance by each of the Buyer and Promega of each of its obligations
contained herein,  have been duly approved by the Buyer's and Promega's Board of
Directors.  No other corporate authorization of the Buyer or Promega is required
for the execution and delivery of this  Agreement or the  performance by them of
their obligations hereunder.

            5.3  Enforceability.  Assuming  the  execution  and  delivery by the
Seller and the  Shareholder  have been duly  authorized,  this Agreement and all
other agreements of the Buyer and Promega  contemplated hereby and, with respect
to Promega,  its  obligations  under  Section  12.2,  are or, upon the execution
thereof,  will be the valid  and  binding  obligations  of each of the Buyer and
Promega  enforceable  against each of the Buyer and Promega,  as applicable,  in
accordance with their terms.

            5.4  Conflicting  Obligations.  The  execution  and delivery of this
Agreement do not, and the consummation of the sale and purchase of the Purchased
Assets will not: (a) conflict with or violate any  provisions of the articles of
incorporation of each of the Buyer and Promega; 


                                      -25-


<PAGE>

            (b)  conflict  with or violate any  provisions  of, or result in the
maturation or acceleration  of, any obligations  under any contract,  agreement,
instrument,  document,  lease, license, permit, indenture, or obligation, or any
law, statute,  ordinance, rule, regulation,  code, guideline, order, arbitration
award,  judgment or decree, to which the Buyer or Promega is subject to or which
the Buyer or Promega is a party;  or (c) conflict  with,  result in a breach of,
constitute a default under,  result in the  acceleration of, create in any party
the right to accelerate,  terminate,  modify,  or cancel,  or require any notice
under any agreement,  contract, lease, license,  instrument or other arrangement
to which the Buyer or Promega is a party or by which it is bound or to which any
of the assets of the Buyer or Promega is subject.

            5.5  Litigation.  There  is  no  litigation,  claim,  proceeding  or
investigation  pending,  or to the Buyer's  Knowledge,  threatened,  against the
Buyer or Promega and  relating  to their  ability to perform  their  obligations
under this Agreement.

            5.6 Brokerage.  Neither the Buyer nor Promega has incurred,  or made
commitment  for, any brokerage,  finders' or similar fee in connection  with the
transactions contemplated by this Agreement.

                                   ARTICLE VI

                   COVENANTS OF THE SELLER AND THE SHAREHOLDER

            The Seller and the Shareholder,  jointly and severally, covenant and
agree with the Buyer as follows:

            6.1  Access.  From the date  hereof  and  until the  earlier  of (i)
termination of this Agreement pursuant to Article XII and (ii) the Closing Date,
the Buyer and its authorized  officers,  agents and  representatives  shall have
full  access  (upon  reasonable  prior  notice)  to  all  properties,   Records,
Contracts, Tax Returns,  management letters, work papers of outside auditors and
other documents of the Seller.  The Seller and the  Shareholder  shall cooperate
with the Buyer by using reasonable efforts to arrange meetings among the Seller,
the Buyer and the Seller's  customers  and suppliers to meet with and respond to
all questions posed by the Buyer  concerning the Seller and promptly  responding
to, and causing the Seller's and the Shareholder's  outside  auditors,  officers
and  employees  promptly  to  respond  to,  all  questions  posed  by the  Buyer
concerning  the Seller,  the Business,  the Purchased  Assets,  or the condition
(financial or otherwise) or prospects of the Seller.

            6.2  Operation  of  Business.  From the date  hereof  and  until the
Closing Date, without the express prior written consent of the Buyer, the Seller
shall not engage in any practice,  take any action or enter into any transaction
outside the Ordinary Course of Business.  Without limiting the generality of the
foregoing, the Seller shall not:

            (a) issue, sell or otherwise dispose of any of its capital stock, or
grant any  options,  warrants or other  rights to purchase or obtain  (including
upon conversion, exchange or exercise) any of its capital stock;


                                      -26-


<PAGE>

            (b) declare,  set aside or pay any dividend or make any distribution
with  respect  to its  capital  stock  (whether  in cash or in kind) or  redeem,
purchase or otherwise acquire any of its capital stock;

            (c)  without  the  prior  approval  of the  Seller,  enter  into any
agreement with Affiliates or any other Person (other than in the Ordinary Course
of Business)  that cannot be  terminated  upon thirty (30) days' notice  without
liability to the Seller and without payment of any  cancellation fee or penalty;
or

            (d) otherwise engage in any practice,  take any action or enter into
any transaction of the sort described in Section 4.28.

            6.3  Preservation  of  Business.  From the date hereof and until the
Closing  Date,  the  Seller  and the  Shareholder  shall  carry on the  Business
substantially  in the  Ordinary  Course of Business  and shall use  commercially
reasonable   efforts  to  keep  the  Business  intact,   including  its  present
relationships with employees, suppliers and customers and others having business
relations  with it.  The Seller  shall use  commercially  reasonable  efforts to
maintain at all times in inventory quantities of raw materials,  finished goods,
spare parts and other  supplies and  materials  sufficient to allow the Buyer to
continue to operate the Business, after the Closing Date, free from any shortage
of such items.

            6.4 Insurance and Maintenance of Property.  From the date hereof and
until the Closing Date,  the Seller shall cause all property  owned or leased by
it to be insured  against all  ordinary  insurable  risks and shall  maintain in
effect all the  Insurance,  and shall  operate,  maintain  and repair all of its
property in a manner consistent with past practice.

            6.5 Compliance with Laws. From the date hereof and until the Closing
Date, the Seller shall comply with all applicable  laws,  statutes,  ordinances,
rules,  regulations,  guidelines,  orders,  arbitration  awards,  judgments  and
decrees applicable to, or binding upon, the Seller or the Business, except where
such noncompliance would not have a Material Adverse Effect.

            6.6 Supplemental Disclosure. On the Closing Date, the Seller and the
Shareholder  shall  inform the Buyer in writing  of all  information,  events or
actions  which,  if this  Agreement  were signed on the Closing  Date,  would be
required to be disclosed on the  Schedules in order to make the Seller's and the
Shareholder's  representations  and  warranties  contained  herein  true and not
misleading.  The delivery  thereof by the Seller and the  Shareholder  shall not
absolve  the  Seller  or  the  Shareholder  from  liability  for  breach  of any
representation or warranty which was untrue when made.

            6.7 Fulfill  Conditions.  The Seller and the  Shareholder  shall use
their best  efforts to cause to be  fulfilled on or prior to the Closing each of
the conditions set forth in Article VIII hereof.

            6.8 Employees.  The Seller shall  terminate the employment of all of
its employees, other than Robert E. Klem.

            6.9  Release of Liens.  The Seller  shall on or prior to the Closing
Date  deliver to the 


                                      -27


<PAGE>

Buyer such  documents as are necessary to terminate and release all Liens on the
Purchased Assets,  except for Permitted Liens,  which documents shall be in form
and substance acceptable to the Buyer and shall include without limitation,  all
documents  necessary to terminate of record all Liens on the  Purchased  Assets,
except for Permitted Liens.

            6.10 Change of Corporate Name. The Seller and the Shareholder  agree
to take all action that is necessary to authorize  the amendment of the Seller's
certificate  of  incorporation  to change the corporate  name of the Seller to a
name which does not include the words "JBL  Scientific"  and/or words of similar
meaning.  At or prior to the  Closing,  the  Seller  and the  Shareholder  shall
provide  the  Buyer  with  documentation  reasonably  satisfactory  to the Buyer
evidencing this amendment.

            6.11  Documents of Transfer.  On the Closing Date,  the Seller shall
duly  execute  and  deliver  to the Buyer (i) the  Assignment,  Bill of Sale and
Assumption  Agreement and (ii)  certificates of title  sufficiently  endorsed to
transfer the Vehicles to the Buyer. Any applicable transfer fee shall be paid by
the Seller at the Closing.

            6.12  Nondisclosure  and  Noncompetition  Agreement.  On the Closing
Date, the Seller,  the  Shareholder and Robert E. Klem shall execute and deliver
to the Buyer the Nondisclosure and Noncompetition Agreement.

            6.13 Other Deliveries. On the Closing Date, the Seller shall deliver
to the Buyer the following:

              (a)    The  resolutions  of the Boards of  Directors of the Seller
                     and the  Shareholder and the Shareholder in its capacity as
                     the  sole   shareholder  of  the  Seller   authorizing  and
                     approving the execution and delivery of this  Agreement and
                     performance  by  the  Seller  and  the  Shareholder  of the
                     transactions  contemplated  hereby,  certified on behalf of
                     the  Seller  and  the  Shareholder,  as  applicable,  by an
                     officer of the Seller and the Shareholder, respectively;

              (b)    Current  Uniform  Commercial  Code  and  state,  local  and
                     federal  tax,  sales  and  unemployment  compensation  tax,
                     judgment,  bankruptcy and similar lien searches  showing no
                     Liens  against the  Purchased  Assets other than  Permitted
                     Liens;

              (c)    All  consents  for  the  assignment  of all  Contracts  and
                     Permits,  which are  necessary in order for said  Contracts
                     and Permits to be assigned to the Buyer upon their  present
                     terms (other than those for which,  individually  or in the
                     aggregate,  would not result in a Material  Adverse Effect)
                     and the Seller shall pay all fees,  charges and other costs
                     that are required or imposed in connection  with  obtaining
                     any such consent;

              (d)    An  affidavit  that the  Seller is not a  "foreign  person"
                     within the meaning of Section 1445 of the Code, and stating
                     the Seller's federal  taxpayer  identification  number,  in
                     form and substance acceptable to counsel for the Buyer; and

              (e)    All other documents reasonably requested by counsel for the
                     Buyer to consummate the transactions herein contemplated.


                                      -28-


<PAGE>

            6.14 Collection of the  Receivables.  After the Closing,  subject to
Section  7.10,  the Buyer shall have full power and authority to collect for its
account all Receivables,  and to endorse, without recourse to the Seller, in the
name of the  Seller,  any checks or other  instruments  of payment  received  on
account of payment of any such  Receivables.  Subject to Section 7.10, if, after
the Closing, the Seller receives any payment on account of any such Receivables,
the Seller shall transfer and deliver such payment (endorsed where necessary) to
the Buyer, promptly after receipt.

            6.15 Exclusive Dealing. Neither the Seller, the Shareholder, nor any
of their agents or representatives will take, directly or indirectly, any action
to initiate, continue, assist, solicit, negotiate, encourage or accept any offer
or inquiry  from any Person (a) to engage in any  Business  Combination,  (b) to
reach  any  agreement  or  understanding  (whether  or  not  such  agreement  or
understanding  is  absolute,  revocable,  contingent  or  conditional)  for,  or
otherwise attempt to consummate,  any Business  Combination or (c) to furnish or
cause to be furnished any  information  with respect to the Seller or its assets
to any Person (other than as  contemplated  in this Agreement) who the Seller or
the Shareholder  knows or has reason to believe is in the process of considering
any Business Combination.  For purposes hereof, "Business Combination" means any
merger,  consolidation  or combination to which the Seller is a party, any sale,
dividend,  split or other  disposition of capital stock or other equity interest
of the Seller or any sale, dividend or other disposition of all or substantially
all of the assets of the Seller.

            6.16  Further  Assurances.  The  Seller  and the  Shareholder,  upon
request  of the  Buyer,  shall  execute,  acknowledge  and  deliver  such  other
instruments  as  reasonably  may be requested to more  effectively  transfer the
Purchased Assets to the Buyer or to otherwise carry out the terms and conditions
of this Agreement.

            6.17 Brokerage.  Any brokerage,  finders' or similar fee incurred in
connection  with  the  transactions  contemplated  by this  Agreement  shall  be
promptly paid by the Seller or the Shareholder.

            6.18 Quality  Assurance  Agreement.  On the Closing Date, the Seller
and the Shareholder shall execute and deliver to the Buyer the Quality Assurance
Agreement.

            6.19 Intellectual Property Assignments. On the Closing Date, each of
the  Seller  and the  Shareholder  shall  execute  and  deliver to the Buyer its
Intellectual Property Assignment.

            6.20 Lipid License  Agreement.  On the Closing Date,  the Seller and
the  Shareholder  shall  execute  and  deliver  to the Buyer  the Lipid  License
Agreement.

            6.21 Biogenex License  Agreement.  The Seller shall have consummated
the  transactions  contemplated by the Biogenex  License  Agreement,  including,
without  limitation,  the licensing of the Amadite  technology to the Seller and
any payments required to be made by the Seller has been made.

            6.22 Note. The Note shall be imprinted  with a legend  substantially
in the following form:


                                      -29-


<PAGE>

            THIS NOTE HAS BEEN ACQUIRED FOR  INVESTMENT  AND NOT WITH A VIEW TO,
            OR FOR SALE IN CONNECTION WITH, ANY  DISTRIBUTION  HEREOF WITHIN THE
            MEANING OF THE  SECURITIES  ACT OF 1933, AS AMENDED.  THE PAYMENT OF
            PRINCIPAL AND INTEREST ON THIS NOTE IS SUBJECT TO CERTAIN RECOUPMENT
            PROVISIONS  SET FORTH IN THIS NOTE AND AN ASSET  PURCHASE  AGREEMENT
            DATED AS OF MARCH 19, 1999 (THE  "PURCHASE  AGREEMENT")  BETWEEN THE
            BUYER (AS DEFINED  BELOW),  JBL  SCIENTIFIC  INCORPORATED  AND GENTA
            INCORPORATED. NOTWITHSTANDING ANY OTHER PROVISIONS CONTAINED HEREIN,
            NO TRANSFER OF THIS NOTE SHALL BE MADE UNLESS  CONDITIONS  SPECIFIED
            IN THE  PURCHASE  AGREEMENT  HAVE  BEEN  FULFILLED.  A  COPY  OF THE
            PURCHASE  AGREEMENT IS ON FILE AND AVAILABLE  FOR  INSPECTION AT THE
            PRINCIPAL OFFICE OF THE BUYER.

The Note shall not be assigned or  transferred  (other than to the  Shareholder)
without  the  express  written  consent of the Buyer.  Each  holder  desiring to
transfer  the Note  first  must  furnish  the Buyer  with (i) a written  opinion
satisfactory to the Buyer in form and substance from counsel satisfactory to the
Buyer by reason of  experience  to the effect that the holder may  transfer  the
Note as desired without registration under the Securities Act and (ii) a written
undertaking executed by the desired transferee satisfactory to the Buyer in form
and  substance  agreeing  to be  bound  by the  recoupment  provisions  and  the
restrictions on transfer contained herein and therein; provided, that the Seller
shall be permitted to transfer the Note to the  Shareholder  without  compliance
with clause (i) above.

            6.23 On-Site  Contamination.  With respect to any further monitoring
and possible cleanup of PCE and chloroform contamination at the facility located
at 277 Granada  Drive,  San Luis Obispo,  California  (that  contamination,  the
"On-Site  Contamination"),  the Seller shall comply promptly with all directives
from the Regional Water Quality Control Board and other Governmental Authorities
to remain in material  compliance with all Environmental  Laws, other than those
directives being contested in good faith through  appropriate legal proceedings.
The Seller  shall  determine  what  actions must be taken after the date of this
Agreement to ensure such compliance. The Seller shall provide the Buyer with any
documents to be submitted to any Governmental Authority,  and shall not take any
action with  respect to the  On-Site  Contamination  without  the Buyer's  prior
consent, which may not be unreasonably withheld and must be promptly provided if
it is to be given.  The Seller  shall bear all costs and  expenses  incurred  in
connection with the On-Site Contamination.

            6.24 The Seller's Welfare Plans.  Effective as of the end of the day
immediately  preceding  the Closing Date,  except as otherwise  provided in this
Section 6.24,  Hired Employees shall cease to be covered by the Seller's Welfare
Plans (as  hereinafter  defined)  except  the  Seller  shall be  liable  for any
vacation pay in excess of four (4) weeks per Hired  Employee that has accrued as
of the Closing Date.  The Seller shall be  responsible  for all of the following
claims  under the  Seller's  Welfare  Plans,  which shall be deemed to have been
"incurred"  prior to the Closing Date:  (i) under any medical,  dental or health
plans for any treatment or service  actually  rendered prior to the Closing Date
(but not rendered thereafter), regardless of whether the service or treatment is
part of 


                                      -30-


<PAGE>

an ongoing course of treatment that  commenced  prior to the Closing Date;  (ii)
under any life  insurance  plans with respect to deaths  occurring  prior to the
Closing  Date;  and (iii) for any  payments  or benefits  otherwise  incurred or
arising prior to the Closing Date under any other  Seller's  Welfare  Plan.  The
Seller shall be  responsible  for providing all employees of the Business  whose
employment is terminated by the Seller and who are covered under a "group health
plan" (within the meaning of Section  5000(b)(1) of the Code)  maintained by the
Seller  (the  "Seller's  Group  Health  Plan"),  and the  qualified  spouses and
dependents of these  employees,  with  continuation  coverage under the Seller's
Group Health Plan to the extent required by the provisions of COBRA as currently
set forth in Part 6 of Subtitle B of Title I of ERISA and  Section  4980B of the
Code,  and the  implementing  regulations  promulgated  or proposed under any of
those laws.  The Buyer shall have no  obligation  to provide,  nor any liability
for,  any  benefits  of  any  kind  under  any of the  Seller's  Welfare  Plans,
including, but not limited to, any COBRA benefits under any group health plan of
the Seller,  except to the extent  related to a failure by the Buyer to meet its
obligations  under  Sections 7.8 and 7.13 hereof.  For purposes of this Section,
the "Seller's  Welfare Plans" shall include each "employee welfare benefit plan"
(within  the  meaning of Section  3(1) of ERISA)  and each other  benefit  plan,
program,  policy or  arrangement  that is maintained by the Seller,  that covers
employees  of the Seller who are employed by the Seller in  connection  with the
Business,  and that is not an "employee pension benefit plan" within the meaning
of Section 3(2) of ERISA.

            6.25  The  Seller's  401(k)  Plan.  The  Seller  maintains  the  JBL
Scientific  Savings and Retirement Plan (the "Seller's  401(k) Plan"), a defined
contribution  profit-sharing  plan with a cash or deferred  arrangement  that is
intended  to be  qualified  under  Sections  401(a) and 401(k) of the Code.  The
Seller shall retain  sponsorship  of the Seller's  401(k) Plan after the Closing
Date and  neither  the  Buyer  nor any plan  maintained  by the  Buyer  shall be
entitled to any assets of the Seller's  401(k) Plan.  The Buyer shall not assume
any responsibility or liability for the Seller's 401(k) Plan, and the Seller and
the  Seller's  401(k) Plan shall  remain  solely and  entirely  responsible  for
satisfying any and all obligations  and  liabilities  arising under the Seller's
401(k)  Plan.  The  accrued  benefits  under  the  Seller's  401(k)  Plan of all
participants are 100% vested and non-forfeitable.

                                   ARTICLE VII

                             COVENANTS OF THE BUYER

            The Buyer  covenants and agrees with the Seller and the  Shareholder
as follows:

            7.1  Certified  Resolutions.  On the Closing  Date,  the Buyer shall
deliver to the Seller a copy of the  resolutions  of the Boards of  Directors of
the Buyer and Promega,  authorizing  and approving the execution and delivery of
this Agreement and the performance by the Buyer and Promega of the  transactions
contemplated  hereby,  as  certified  on behalf of the  Buyer  and  Promega,  as
applicable, by an officer of the Buyer and Promega, respectively.

            7.2  Assignment,  Bill  of Sale  and  Assumption  Agreement.  On the
Closing Date, the Buyer shall execute and deliver to the Seller the  Assignment,
Bill of Sale and Assumption Agreement.


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<PAGE>

            7.3 Nondisclosure and Noncompetition Agreement. On the Closing Date,
the Buyer  shall  execute  and  deliver to the Seller  and the  Shareholder  the
Nondisclosure and Noncompetition Agreement.

            7.4 Quality  Assurance  Agreement.  On the Closing  Date,  the Buyer
shall  execute  and  deliver  to the  Seller  and the  Shareholder  the  Quality
Assurance Agreement.

            7.5 Lipid License  Agreement.  On the Closing Date,  the Buyer shall
execute and deliver to the Shareholder the Lipid License Agreement.

            7.6 Note. On the Closing  Date,  the Buyer shall execute and deliver
to the Seller the Note.

            7.7 Lease.  On the Closing Date, the Buyer shall execute and deliver
to Granada Associates, LLC the Lease.

            7.8   Employees.   On  the  Closing  Date,  the  Buyer  shall  offer
employment,  effective as of the Closing  Date,  to all  full-time and part-time
employees of the Seller,  other than Robert E. Klem,  who are active or on leave
for medical or disability reasons or are covered by the Family and Medical Leave
Act of 1993, P.L. 103-3,  with employee  benefits and perquisites  which, in the
aggregate, are substantially comparable to the employee benefits and perquisites
set forth on Schedule 7.8;  provided,  that each  employee  shall receive a base
salary that is no less favorable than the base salary set forth on Schedule 7.8.
Employees  of the Seller who accept the  Buyer's  offers of  employment  and who
become  employees  of the Buyer as of the Closing Date are referred to herein as
"Hired Employees."

            7.9 Preservation of Records.  Subject to the following sentence, the
Buyer shall at its own expense (a) preserve and keep the Records for a period of
five (5) years  from the  Closing  and (b) make the  Records  and its  personnel
available to the Seller or the  Shareholder at their  request.  In the event the
Buyer wishes to destroy any Records  during the time specified  above,  it shall
first  give  thirty  (30)  days'  prior  written  notice to the  Seller  and the
Shareholder  and the  Seller  and the  Shareholder  shall  have the right at its
option and  expense,  upon prior  written  notice given to the Buyer within that
thirty (30) day period,  to take  possession  of the records  within thirty (30)
days after the date of the Seller's notice to the Buyer.

            7.10 Uncollectible Receivables.

            (a) The Buyer shall  promptly  assign each  Receivable to the Seller
upon the end of the 120-day period following the Closing Date.

            (b) The Buyer  shall  afford the Seller  and its  representatives  a
reasonable  opportunity,  during normal business hours, to examine and audit the
books and records of the Buyer with respect to the collection of Receivables.

            (c) For purposes of determining the collections on Receivables,  any
payments  received by the Buyer shall be applied against the oldest account owed
by the Person making the payment 


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<PAGE>

unless that Person  indicates to the Buyer that that  account is in dispute,  in
which event the payment shall be applied against the next oldest Receivable.

            (d) The Buyer shall maintain appropriate records with respect to the
Receivables and shall act in good faith to collect the Receivables in accordance
with the Seller's  past  practices for the  collection  of accounts  receivable;
provided,  however, that in no event shall the Buyer be required to institute or
threaten litigation or refuse to accept any purchase order.

            (e) All  proceeds  of any  Receivable  assigned  by the Buyer to the
Seller  pursuant to Section  7.10(a)  that are  collected by the Buyer after the
date that  Receivable was so assigned  shall be promptly  remitted by the Buyer.
The Buyer  shall  provide to the Seller a copy of such  records  relating to the
Receivables so assigned to the Seller as the Seller may request,  such copies to
be delivered within ten (10) days after the pertinent  Receivable is so assigned
or after such request is made, whichever is later.

            7.11  Access to  Property.  From the Closing  Date,  the Buyer shall
cooperate with the Seller and shall provide the Seller with reasonable access at
reasonable  times to the  facility  located at 277  Granada  Drive,  so that the
Seller may oversee any  monitoring  and cleanup  activities  with respect to the
On-Site  Contamination  required by the Regional  Water  Quality  Control  Board
directives.  From the Closing Date, the Buyer shall allow the Seller to use Greg
Frank for up to fifteen (15) hours each month to assist in the Seller's  efforts
to comply with all directives,  monitoring and clean-up at the facility  located
at 277 Granada Drive;  provided,  that each hour Greg Frank spends assisting the
Seller  shall  reduce  the  Buyer's  obligations  under  the  Quality  Assurance
Agreement by one hour.

            7.12 The Buyer's 401(k) Plan.  Promega  maintains the Promega Profit
Sharing  and  Salary  Deferral  Plan  (the  "Promega  401(k)  Plan"),  a defined
contribution  profit-sharing  plan with a cash or deferred  arrangement  that is
intended to be qualified under Sections 401(a) and 401(k) of the Code. As of the
Closing Date,  coverage  under the Promega  401(k) Plan shall be extended to all
Hired Employees and credit under the Promega 401(k) Plan shall be given to Hired
Employees  for all  their  service  with the  Seller,  solely  for  purposes  of
eligibility  to participate  and vesting,  to the same extent such service would
have been credited if the service had been  performed  for Promega,  and Promega
shall  cause the  Promega  401(k)  Plan to be  amended,  to the  extent (if any)
necessary,  to provide for this crediting of service with the Seller.  After the
Closing  Date,  Promega  shall permit Hired  Employees  who are entitled and who
elect to receive an eligible rollover distribution from the Seller's 401(k) Plan
to direct that the eligible rollover  distribution be transferred to the Promega
401(k) Plan in  accordance  with  Section  402(c) of the Code and Promega  shall
cause the Promega 401(k) Plan to be amended,  to the extent (if any)  necessary,
to permit such transfers.

            The Buyer shall be responsible for all of the following claims under
the Buyer's  Welfare  Plans,  which shall be deemed  "incurred"  on or after the
Closing Date: (i) under any medical, dental or health plans for any treatment or
service  actually  rendered  on or after (but not  rendered  before) the Closing
Date,  regardless  of whether  the  service or  treatment  is part of an ongoing
course of treatment  that  commenced  prior to the Closing Date,  (ii) under any
life  insurance  plans with respect to deaths  occurring on or after the Closing
Date,  and (iii) for any  payments or benefits  incurred on or after the Closing
Date under any other Buyer Welfare Plan.


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<PAGE>

            7.13 The  Buyer's  Welfare  Plans.  The Buyer  shall  not  assume or
continue any of the Seller's  Benefit  Plans.  As of the Closing Date, the Buyer
shall provide Hired Employees with employee  benefit plans,  programs,  policies
and  arrangements  (the  "Buyer's  Welfare  Plans") that provide  benefits on an
aggregate basis which are comparable to the benefits provided to Hired Employees
immediately prior to the Closing under the Seller's Welfare Plans.  Specifically
with  respect to medical  and other  health-related  benefits,  the Buyer  shall
provide  each  Hired  Employee  (and  each such  Hired  Employee's  spouses  and
dependents) with immediate coverage as of the Closing Date under a "group health
plan"  (within the  meaning of Section  5001(b) of the Code)  maintained  by the
Buyer (the  "Buyer's  Group Health  Plan") that  provides  benefits and includes
terms and  conditions  which are  substantially  similar  to or better  than the
benefits  provided and terms and  conditions  included  under the Seller's group
health plan in which each Hired Employee  participated  immediately prior to the
Closing,  and the Buyer shall waive any  pre-existing  condition  exclusions  or
restrictions with respect to Hired Employees under the Buyer's Group Health Plan
to the same extent as coverage is provided under the Seller's Group Health Plan.
Each Hired Employee shall receive credit under the Buyer's group health plan for
all amounts paid by each Hired Employee in calendar year 1999 under the Seller's
group health plan for purposes of any  applicable  deductibles,  co-payments  or
out-of-pocket  maximums.  The Buyer shall be solely  responsible  for  providing
Hired Employees with any continuation coverage (and shall have sole liability in
respect of any failure to provide  such  continuation  coverage)  under  Section
4980B of the Code or Part 6 of Subtitle B or Title I of ERISA resulting from any
"qualifying event" occurring on or after the Closing Date. The Buyer shall grant
full credit to Hired  Employees,  under the Buyer's  Welfare  Plans that are not
group health plans, for service with the Seller (or with a predecessor  employer
to the  extent  credited  under the  corresponding  Seller's  Welfare  Plan) for
purposes  of  (i)  satisfying  any  and  all   eligibility   and   participation
requirements under the Buyer's Welfare Plans and (ii) determining the amount and
duration  of any  benefits  under the Buyer's  Welfare  Plans to the extent that
service or seniority is a  consideration  in calculating  benefits but the Buyer
shall not be required to credit any service that would  result in a  duplication
of benefits.  The Seller shall have no obligation to provide,  nor any liability
for,  any  benefits  of any kind to Hired  Employees  under  any of the  Buyer's
Welfare Plans,  including,  but not limited to, COBRA benefits under any Buyer's
Group Health Plan.

            7.14 Employment  Terms and Benefits after the Closing Date.  Nothing
in this  Agreement  shall be construed to limit or restrict the Buyer in any way
after the Closing Date with respect to (i) the Buyer's  conduct of the Business;
(ii) the Buyer's  modification  or change in the terms of employment  (including
the  termination  of employment)  of any Hired  Employee;  and (iii) the Buyer's
modification,  amendment or termination of any employee  benefit plan maintained
or contributed to by the Buyer,  including but not limited to any of the Buyer's
Welfare Plans; provided, however, within ninety (90) days from the Closing Date,
no such amendment or  modification  shall be  inconsistent  with the requirement
that Hired  Employees  receive  immediate  coverage  under a group  health  plan
pursuant to Section 7.13.

            7.15 Product Liability Claims. If the Buyer  successfully  asserts a
claim  against  the Seller or the  Shareholder  with  respect to a breach of the
representations  or  warranties  contained  in  Section  4.26,  the Buyer  shall
promptly  assign any rights and remedies,  under warranty or otherwise,  against
the  manufacturers,  vendors or other  Persons for any  defects in the  Purchase
Asset giving rise to such claim.


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<PAGE>

            7.16 Minimum Net Book Value.  From and after the Closing Date, until
the third  anniversary  of the Closing  Date,  the Buyer shall not cause its Net
Book Value to be more than $500,000  less than the Final Net Book Value,  unless
Promega  agrees to  indemnify  the Seller and the  Shareholder  with  respect to
Assumed  Liabilities  as set  forth in  Article  XI and to  assume  the  Buyer's
obligations under Article XI.

                                  ARTICLE VIII

                  CONDITIONS OF THE BUYER'S OBLIGATION TO CLOSE

            The  obligation  of  the  Buyer  to  consummate   the   transactions
contemplated  by  this  Agreement  shall  be  subject  to the  satisfaction  and
fulfillment  or  waiver,  prior to and on the  Closing  Date,  of the  following
express conditions precedent:

            8.1  Representation   and  Warranties.   The   representations   and
warranties in this  Agreement  made by the  Shareholder  and the Seller shall be
true and correct in all material respects as of and at the Closing Date with the
same force and effect as though said  representations  and  warranties  had been
again made on the Closing Date, and each of the Seller and the Shareholder shall
have  furnished the Buyer a  certificate  to that effect signed on behalf of the
Seller and the Shareholder and by an officer of the Seller and the  Shareholder,
respectively.

            8.2  Performance of Covenants and  Obligations.  The Shareholder and
the Seller shall have  performed and complied in all material  respects with all
of  their  covenants  and  obligations  under  this  Agreement  which  are to be
performed or complied with by them prior to or on the Closing Date,  and each of
the Seller and the  Shareholder  shall have furnished the Buyer a certificate to
that effect signed on behalf of the Shareholder and the Seller and by an officer
of the Seller and the Shareholder, respectively.

            8.3  Proceedings  and  Instruments  Satisfactory.  All  proceedings,
corporate  or  otherwise,  to be  taken  in  connection  with  the  transactions
contemplated by this Agreement,  and all documents  incident  thereto,  shall be
satisfactory  in form and  substance  to the Buyer.  The Seller  shall have made
available to the Buyer for  examination the originals or true and correct copies
of all documents  which the Buyer  reasonably may request in connection with the
transactions contemplated by this Agreement.

            8.4 Adverse  Change.  From and after the date of this  Agreement and
until the Closing Date, the Buyer shall have  reasonably  determined  that there
has been no event or condition  which has resulted in a Material  Adverse Effect
in the Business.  Each of the Seller and the  Shareholder  shall have  furnished
with the Buyer a certificate to that effect signed on behalf of the  Shareholder
and  the  Seller  and  by  an  officer  of  the  Seller  and  the   Shareholder,
respectively.

            8.5  No  Litigation.   No  investigation,   suit,  action  or  other
proceeding shall be threatened or pending before any  Governmental  Authority in
which it is sought to  restrain,  prohibit or obtain  


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<PAGE>

damages or other relief in connection with this Agreement or the consummation of
the transactions contemplated hereby.

            8.6 Consents, Approvals,  Certifications,  Licenses and Permits. All
necessary consents, approvals, certifications, licenses and permits with respect
to the transaction  contemplated  hereby,  including,  without  limitation,  the
transfer of the Purchased Assets to the Buyer, the absence of which would have a
Material Adverse Effect.

            8.7 Good Standing Certificates. The Seller and the Shareholder shall
have delivered to the Buyer current  certificates  of good standing  relative to
the Seller and the Shareholder  recently  certified by the Secretary of State or
other appropriate  governmental authority of each state or jurisdiction in which
the Seller and the  Shareholder,  as  applicable,  are organized or qualified to
transact business.

            8.8 Opinion of  Counsel.  On the  Closing  Date,  the Seller and the
Shareholder shall have delivered to the Buyer the legal opinions of Kramer Levin
Naftalis & Frankel LLP and Sinsheimer,  Schiebelhut & Baggett, the Shareholder's
and the Seller's  counsel,  in  substantially  the form of Exhibits A-1 and A-2,
respectively, attached hereto.

            8.9 Due  Diligence.  On or prior to March 22, 1999,  the Buyer shall
have conducted a due diligence investigation and review of the Purchased Assets,
the Assumed  Liabilities,  the Business and all matters  pertaining thereto that
the Buyer deems relevant and the results of such  investigation and review shall
be  satisfactory  to the Buyer in its sole and absolute  discretion,  including,
without  limitation,  any due diligence  investigation  relating to the Seller's
Intellectual Property and existing  Environmental Claims. This Section 8.9 shall
terminate on 12:01 a.m. Eastern Time on March 23, 1999.

            8.10 Approval by the Shareholder's  Shareholders.  A majority of the
voting  power of the  Shareholder's  holders  of voting  securities  shall  have
delivered to the Shareholder a written consent in the form previously  delivered
to the Buyer.

            8.11 Lease.  Granada  Associates,  LLC shall have  entered  into the
Lease.

                                   ARTICLE IX

                 CONDITIONS TO THE SELLER'S OBLIGATION TO CLOSE

            The  obligation of the Seller and the  Shareholder to consummate the
transactions contemplated by this Agreement shall be subject to the satisfaction
and  fulfillment  or waiver,  prior to and on the Closing Date, of the following
express conditions precedent:

            9.1   Representations   and  Warranties.   The  representations  and
warranties  in this  Agreement  made by the Buyer and Promega  shall be true and
correct in all  material  respects as of and at the  Closing  Date with the same
force and effect as though said  representations  and  warranties had been again
made on the Closing Date, and each of the Buyer and Promega shall have furnished
the  Seller a  certificate  to that  effect  signed  on  behalf of the Buyer and
Promega by an officer of the Buyer and Promega, respectively.


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<PAGE>

            9.2 Performance of Covenants and Obligations.  The Buyer and Promega
shall have  performed and complied  with all of its  covenants  and  obligations
under this  Agreement  which are to be performed or complied with by it prior to
or on the Closing Date,  and each of the Buyer and Promega shall have  furnished
the  Seller a  certificate  to that  effect  signed  on  behalf of the Buyer and
Promega by an officer of the Buyer and Promega, respectively.

            9.3  Proceedings  and  Instruments  Satisfactory.  All  proceedings,
corporate  or  otherwise,  to be  taken  in  connection  with  the  transactions
contemplated by this Agreement,  and all documents  incident  thereto,  shall be
reasonably  satisfactory  in form and  substance  to the Seller;  and, the Buyer
shall have made  available to the Seller for  examination  the originals or true
and correct  copies of all documents  which the Buyer  reasonably may request in
connection with the transactions contemplated by this Agreement.

            9.4  No  Litigation.   No  investigation,   suit,  action  or  other
proceeding shall be threatened or pending before any  Governmental  Authority in
which it is sought to  restrain,  prohibit or obtain  damages or other relief in
connection  with  this  Agreement  or  the   consummation  of  the  transactions
contemplated hereby.

            9.5 Opinion of Counsel.  On the Closing Date,  the Buyer and Promega
shall have  delivered  the legal  opinion of Michael  Best & Friedrich  LLP, the
Buyer's and Promega's counsel, in substantially the form of Exhibit A-3 attached
hereto.

                                    ARTICLE X

                    INDEMNIFICATION BY SELLER AND SHAREHOLDER

            10.1 Indemnification. Notwithstanding the Closing, and regardless of
any investigation  made by, or on behalf of, the Buyer, or any information known
to the Buyer, the Seller and the Shareholder (collectively,  the "Indemnitors"),
subject to the terms and  conditions  of this Article X, jointly and  severally,
indemnify and save the Buyer, its shareholders, officers, directors or employees
(collectively,  the "Buyer" as used in this Article X) harmless from and against
any  and  all  losses,  claims,   damages,   liabilities,   costs,  expenses  or
deficiencies including, but not limited to, reasonable attorneys' fees and other
costs and expenses, and including simple interest thereon at the Applicable Rate
(collectively, "Losses") reasonably incident to proceedings or investigations or
the  defense or  settlement  of any claim or  claims,  incurred  by or  asserted
against the Buyer or the  Purchased  Assets due to or resulting  from any of the
following: (a) the inaccuracy or breach of any representation or warranty of the
Seller or the Shareholder given in or pursuant to this Agreement; (b) any breach
or default in the  performance by the Seller or the  Shareholder of any of their
covenants,  obligations or agreements in or pursuant to this Agreement;  (c) any
liability  or  obligation  of the  Seller  not  expressly  assumed  by the Buyer
pursuant to this Agreement;  and (d) the ownership or conduct of the Business or
the ownership or use of the Seller's assets at any time prior to the Closing, or
any incident, occurrence, condition or claim existing, arising or accruing prior
to the Closing and  relating to the  operation or conduct of the Business or the
ownership or use of the Seller's  assets  (including,  without  limitation,  all
Losses due to Environmental Claims,  Environmental  Releases by any Person prior
to the  Closing  Date)  other than any  liability  or  obligation  of the Seller
expressly  assumed by the Buyer  pursuant to this  Agreement.  The foregoing are
collectively  referred to as  "Indemnifiable  Damages." The term  "Indemnifiable
Damages"  shall  also  include  an  amount  of  interest  on the  amount of such
Indemnifiable Damages (computed before the application of this sentence),  which
interest shall be computed at the Applicable  Rate in simple  interest per annum
from the Closing Date and until paid by the Indemnitors.

            10.2 Procedures for Making Claims.  If and when the Buyer desires to
assert a claim for Indemnifiable Damages against the Indemnitors pursuant to the
provisions  of this  Article  X, the Buyer  shall  deliver  to the  Indemnitors,
reasonably  promptly  after  the  Buyer's  receipt  of a claim or  specific  and
affirmative  awareness of a potential claim, a certificate  signed by an officer
(the  "Notice of  Claim"):  (a)  stating  that the Buyer has paid or accrued (or
intends  to pay or accrue)  Indemnifiable  Damages  to which it is  entitled  to
indemnification pursuant to this Article X and the amount thereof (to the extent
then known);  and (b) specifying to the extent possible (i) the individual items
of loss, damage,  liability,  cost, expense or deficiency included in the amount
so stated, (ii) the date each such item was or will be paid or accrued and (iii)
the basis upon which Indemnifiable Damages are claimed. If the Indemnitors shall
object to such Notice of Claim,  the Indemnitors  shall  simultaneously  deliver
written  notice of  objection  (the "Notice of  Objection")  to the Buyer within
thirty (30) days after the Buyer's  delivery of the Notice of Claim.  The Notice
of Objection  shall set forth the grounds upon which the  objection is based and
state  whether  the  Indemnitors  object to all or only a portion  of the matter
described in the Notice of Claim. If the Notice of Objection shall not have been
so  delivered  within  such thirty (30) day  period,  all  Indemnitors  shall be
conclusively  deemed to have acknowledged the correctness of the claim or claims
specified  in the  Notice  of  Claim  for  the  full  amount  thereof,  and  the
Indemnifiable  Damages  set forth in the  Notice  of Claim  shall be paid to the
Buyer, on demand, in cash.


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<PAGE>

            10.3  Participation  in Defense of Third Party Claims.  If any third
party shall  assert any claim  against the Buyer  which,  if  successful,  might
result in an  obligation of the  Indemnitors  to pay  Indemnifiable  Damages and
which can be remedied to the reasonable satisfaction of the Buyer by the payment
of  money  damages  without  further  adverse  consequence  to  the  Buyer,  the
Indemnitors,  at the sole  expense of the  Indemnitors,  may assume the  primary
defense thereof with counsel reasonably acceptable to the Buyer, but only if and
so long as: (a) the Indemnitors diligently pursue the defense of such claim; and
(b) the  Indemnitors  acknowledge  to the Buyer in writing  that the  claim,  if
resolved  or  settled  with an  acknowledgement  that  the  Indemnitors  have an
indemnification claim hereunder,  is one for which the Indemnitors are obligated
to indemnify the Buyer  hereunder.  Except with the prior written consent of the
Buyer,  which shall not be  unreasonably  withheld,  the  Indemnitors  shall not
consent to entry of any judgment,  or enter into any  settlement,  that provides
for injunctive or other nonmonetary  relief affecting the Buyer or that does not
include  as an  unconditional  term  thereof  the  giving  by each  claimant  or
plaintiff  to the Buyer of a release  from all  liability  with  respect to such
claim or litigation. If the Indemnitors fail or are unable to so elect to assume
the primary  defense of any such  claim,  the Buyer may (but need not) do so, in
which event the Buyer may defend, settle or compromise the claim, at the expense
and cost of the  Indemnitors,  in any such manner as the Buyer  reasonably deems
appropriate;  provided,  that,  except  with the prior  written  consent  of the
Indemnitors,  which  shall not be  unreasonably  withheld,  the Buyer  shall not
consent to entry of any judgment,  or enter into any  settlement,  that provides
for injunctive or other  nonmonetary  relief affecting either of the Indemnitors
or that does not  include as an  unconditional  term  thereof the giving by each
claimant or plaintiff to the  Indemnitors  of a release from all liability  with
respect to such claim or litigation.

            10.4   Survival  of   Representations   and   Indemnification.   The
Indemnitor's  obligation  to pay  Indemnifiable  Damages  arising  out of claims
described  in Sections  10.1(b),  (c) and (d) shall  survive the Closing of this
transaction  indefinitely.  The  representations  and  warranties  contained  in
Article IV, and the Indemnitor's obligation to pay Indemnifiable Damages arising
out of Section 10.1(a) hereof, shall survive the Closing Date, as follows:

            (a) Fraudulent Breach of Representations;  Certain  Representations.
In the case of a claim based upon the  inaccuracy or breach of a  representation
or warranty which was made fraudulently or with respect to any representation or
warranty  contained  in Sections  4.1,  4.2,  4.3,  4.4(a),  4.5,  4.6 and 4.30,
indefinitely;

            (b)  Taxes;  Environmental.  In the case of a claim  based  upon the
inaccuracy or breach of a representation or warranty  contained in Sections 4.21
and 4.23, for a period equal to the applicable statute of limitations;

            (c) Inventories. In the case of a claim based upon the inaccuracy or
breach of a  representation  or warranty  contained in Section  4.14,  until the
Closing Balance Sheet has been finalized  pursuant to Section 2.2(c)-(d) and any
required payment has been made pursuant to Section 2.2(f); and


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<PAGE>

            (d) All Other Claims. In the case of all other claims based upon the
inaccuracy  or breach of any  other  representation  or  warranty  contained  in
Article  IV, for a period  commencing  on the date  hereof and ending  three (3)
years after the Closing Date.

No claim for  recovery of  Indemnifiable  Damages  arising  out of Section  10.1
hereof may be asserted by the Buyer after the expiration of the applicable  time
period described in this Section 10.4; provided,  however,  that any claim first
asserted  by the  giving of a Notice of Claim  within  the  applicable  survival
period shall neither be abated nor barred.

            10.5  Limitations  on  Indemnifiable  Damages.  Notwithstanding  the
foregoing,  other than  Indemnifiable  Damages  (a) due to fraud or  intentional
misrepresentation  on behalf of the Seller or the Shareholder or (b) arising out
of an  inaccuracy  or breach of any  representations  or warranty  contained  in
Sections 4.1, 4.2, 4.3,  4.4(a),  4.5, 4.6, 4.21, 4.23 and 4.30, for which there
shall be no  limitation  on the  Seller's  breach,  (x) the  maximum  amounts of
Indemnifiable  Damages payable by the Seller and the  Shareholder  arising under
Section  10.1(a) shall not exceed the Purchase Price and (y) the Buyer shall not
be entitled to recover Indemnifiable Damages for any matter described in Section
10.1(a) unless and until the aggregate of all claims for  Indemnifiable  Damages
asserted pursuant to Section 10.1(a) exceeds $25,000.

            10.6  Offset.  The Buyer  shall be  entitled  to offset  against any
obligations  owed by the Buyer to the Indemnitors  the sum of all  Indemnifiable
Damages  that the  Buyer is  entitled  to  pursuant  to  Article X and all other
obligations  owed by the Buyer to the  Indemnitors  under  any other  agreement,
contract or other arrangement. Without limiting the generality of the foregoing,
the  Buyer  shall  have  the  option  of  recouping  all  or  any  part  of  any
Indemnifiable  Damages it may suffer (in lieu of seeking any  indemnification to
which it is  entitled  under this  Article X) by  notifying  the Seller that the
Buyer is reducing the  principal  amount  outstanding  under the Note. No offset
made by the Buyer pursuant to this Section 10.6 shall constitute a default under
any of the Buyer's payment obligations or, even if it is subsequently determined
that no Indemnifiable Damages or other obligations were due the Buyer, give rise
to any right of acceleration under the Note or any other agreement,  contract or
understanding on the part of any of the Indemnitors by reason of such offset.

            10.7 Other Indemnification Provisions. The foregoing indemnification
provisions  are in  addition  to,  and  not in  derogation  of,  any  statutory,
equitable,  or common law remedy (including  without  limitation any such remedy
arising under  Environmental Law) the Buyer may have with respect to the Seller,
the   Shareholders   or  the   transactions   contemplated  by  this  Agreement.
Notwithstanding the foregoing,  each of the Buyer and Promega hereby agrees that
it will not make, and agrees that its officers,  directors or employees will not
make, any claim for indemnification against any Person who is or was a director,
officer,  employee,  or agent of any of the Seller,  the  Shareholder  and their
Affiliates  or was  serving  at the  request  of any such  entity as a  partner,
trustee,  director,  officer,  employee,  or agent of another  entity (each such
Person, a "Protected  Shareholder Person") (whether such claim is for judgments,
damages, penalties, fines, costs, amounts paid in settlement,  losses, expenses,
or  otherwise  and  whether  such  claim is  pursuant  to any  statute,  charter
document,  bylaw,  agreement,  or otherwise)  with respect to any action,  suit,
proceeding,  complaint,  claim,  or demand  brought  by the Buyer or  Promega in
connection with the transactions contemplated by this Agreement.


                                      -40-


<PAGE>

                                   ARTICLE XI

                            INDEMNIFICATION BY BUYER

            11.1 Indemnification. Notwithstanding the Closing, and regardless of
any  investigation  made by, or on behalf of, the Seller or Shareholder,  or any
information known to the Seller or Shareholder,  the Buyer, subject to the terms
and  conditions  of this  Article XI,  indemnifies  and saves the Seller and the
Shareholder   and  their   shareholders,   officers,   directors   or  employees
(collectively,  the "Indemnitees") harmless from and against any and all Losses,
reasonably   incident  to  proceedings  or  investigations  or  the  defense  or
settlement  of  any  claim  or  claims,  incurred  by or  asserted  against  the
Indemnitees  due to:  (a) the  inaccuracy  or  breach of any  representation  or
warranty of the Buyer or Promega given in or pursuant to this Agreement; (b) any
breach or  default  in the  performance  by the  Buyer of any of its  covenants,
obligations  or  agreements  in or pursuant to this  Agreement;  (c) any Assumed
Liabilities;  (d) Losses  relating to the  operations of the Business  after the
Closing Date, including, without limitation,  Losses from Environmental Releases
caused by the operations of the Business and Environmental Claims resulting from
the  operations of the Business  after the Closing;  and (e) Losses arising from
the Buyer's due  diligence  activities  at the Real Estate prior to the Closing,
including, without limitation any soil or groundwater testing conducted by or on
behalf of the Buyer.  The  foregoing  are  collectively  referred  to as "Seller
Indemnifiable  Damages."  The term  "Seller  Indemnifiable  Damages"  shall also
include  an amount of  interest  on the  amount  of such  Indemnifiable  Damages
(computed  before the  application  of this  sentence),  which interest shall be
computed at the  Applicable  Rate simple  interest  per annum from the date such
Seller Indemnifiable Damages were incurred by the Indemnitees and until paid.

            11.2  Procedures  for  Making  Claims.  If and when the  Indemnitees
desire to assert a claim for  Seller  Indemnifiable  Damages  against  the Buyer
pursuant to the provisions of this Article XI, the Indemnitees  shall deliver to
the Buyer,  reasonably  promptly  after the  Indemnitees'  receipt of a claim or
awareness of a potential  claim, a certificate  signed by the  Indemnitees  (the
"Seller Notice of Claim"): (a) stating that the Indemnitees have paid or accrued
(or  intend to pay or  accrue)  Seller  Indemnifiable  Damages to which they are
entitled to  indemnification  pursuant to this Article XI and the amount thereof
(to the extent then known);  and (b)  specifying to the extent  possible (i) the
individual  items  of loss,  damage,  liability,  cost,  expense  or  deficiency
included  in the amount so  stated,  (ii) the date each such item was or will be
paid or accrued and (iii) the basis upon which Seller Indemnifiable  Damages are
claimed.  If the Buyer  shall  object to such  Notice of Claim,  the Buyer shall
deliver  written  notice of objection  (the "Seller Notice of Objection") to the
Indemnitees  within  thirty  (30) days after the  Indemnitee's  delivery  of the
Seller  Notice of Claims.  The Seller  Notice of  Objection  shall set forth the
grounds upon which the objection is based and state whether the Buyer objects to
all or only a portion of the matter  described in the Seller Notice of Claim. If
the Seller  Notice of Claim shall not have been so delivered  within such thirty
(30) day period, the Buyer shall be conclusively deemed to have acknowledged the
correctness  of the claim or claims  specified in the Seller Notice of Claim for
the full amount  thereof and the Seller  Indemnifiable  Damages set forth in the
Seller Notice of Claim shall be paid to the Indemnitees, on demand, in cash.


                                      -41-


<PAGE>

            11.3  Participation  in Defense of Third Party Claims.  If any third
party shall assert any claim against the Indemnitees which, if successful, might
result in an obligation of the Buyer to pay Seller  Indemnifiable  Damages,  and
which  can be  remedied  to the  reasonable  satisfaction  of the  Seller by the
payment of money damages without further adverse consequences to the Seller, the
Buyer, at the sole expense of the Buyer,  may assume the primary defense thereof
with counsel reasonably  acceptable to the Indemnitees,  but only if and so long
as: (a) the Buyer  diligently  pursues the  defense of such  claim;  and (b) the
Buyer  acknowledges to the Indemnitees in writing that the claim, if resolved or
settled  with an  acknowledgement  that the Buyer has an  indemnification  claim
hereunder,  is one for which the Buyer is obligated to indemnify the Indemnitees
hereunder. Except with the prior written consent of the Indemnitees, which shall
not be  unreasonably  withheld,  the  Buyer  shall not  consent  to entry of any
judgment,  or enter into any  settlement,  that provides for injunctive or other
nonmonetary  relief  affecting  the  Indemnitees  or that does not include as an
unconditional  term  thereof  the giving by each  claimant or  plaintiff  to the
Indemnitees  of a release  from all  liability  with  respect  to such  claim or
litigation.  If the Buyer  fails or refuses  so to elect to assume  the  primary
defense of any such claim,  the  Indemnitees  may (but need not) do so, in which
event the  Indemnitees  may defend,  settle or compromise  the claim in any such
manner as the Indemnitees  reasonably deem  appropriate;  provided,  that except
with the prior  written  consent of the Buyer,  which shall not be  unreasonably
withheld,  the Indemnitees shall not consent to entry of any judgment,  or enter
into any settlement,  that provides for injunctive or other  nonmonetary  relief
affecting  the Buyer or that does not include as an  unconditional  term thereof
the giving by each  claimant  or  plaintiff  to the Buyer of a release  from all
liability with respect to such claim or litigation.

            11.4  Survival of  Indemnification.  The Buyer's  obligation  to pay
Seller Indemnifiable Damages arising out of claims described in Section 11.1(b),
(c), (d) and (e) shall survive the Closing of this transaction indefinitely. The
representations   and  warranties   contained  in  Article  V  and  the  Buyer's
obligations to pay  Indemnifiable  Damages  arising out of Section 11.1(a) shall
survive the Closing Date, as follows:

            (a) Fraudulent Breach of Representations;  Certain  Representations.
In the case of a claim based upon the  inaccuracy or breach of a  representation
or warranty which was made fraudulently or with respect to any representation or
warranty contained in Sections 5.1, 5.2, 5.3, 5.4(a) and 5.6, indefinitely; and

            (b) All Other Claims. In the case of all other claims based upon the
inaccuracy or breach of a representation or warranty contained in Article V, for
a period  commencing  on the date  hereof and ending  three (3) years  after the
Closing Date.

No claim for recovery of  Indemnifiable  Damages  arising out of Section 11.1(a)
hereof may be asserted by the Indemnitee  after the expiration of the applicable
time period described in this Section 11.4;  provided,  however,  that any claim
first  asserted by the giving of a Seller Notice of Claim within the  applicable
survival period shall neither be abated nor barred.

            11.5  Limitations  on  Indemnifiable  Damages.  Notwithstanding  the
foregoing,  other  than  Seller  Indemnifiable  Damages  (a)  due  to  fraud  or
intentional  misrepresentation  on behalf of the Buyer or Promega or (b) arising
out of an inaccuracy or breach of any  representation  or warranty  contained in
Sections 5.1, 5.2, 5.3,  5.4(a) or 5.6, for which there shall be no  limitation,
(x) the  


                                      -42-


<PAGE>

maximum  amount of Seller  Indemnifiable  Damages on the  Buyer's  or  Promega's
breach  payable by the Buyer arising under Section  11.1(a) shall not exceed the
Purchase  Price and (y) the  Seller  shall not be  entitled  to  recover  Seller
Indemnifiable  Damages for any matter  described in Section  11.1(a)  unless and
until the aggregate of all claims for Indemnifiable Damages asserted pursuant to
Section 11.1(a) exceeds $25,000.

            11.6  Offset.  The Seller and the  Shareholder  shall be entitled to
offset  against any  obligations  owed by the Seller or the  Shareholder  to the
Buyer or Promega the sum of all Seller Indemnifiable  Damages that the Seller or
the Shareholder is entitled to pursuant to Article XI and all other  obligations
owed by the Seller or the  Shareholder  to the Buyer or Promega  under any other
agreement,  contract or other  arrangement.  No offset made by the Seller or the
Shareholder  pursuant to this Section 11.6 shall  constitute a default under any
of the  Seller's  or the  Shareholder's  payment  obligations  or, even if it is
subsequently   determined  that  no  Seller   Indemnifiable   Damages  or  other
obligations  were due the Seller or the  Shareholder,  give rise to any right of
acceleration under any other agreement, contract or understanding on the part of
the Seller or the Shareholder by reason of such offset.

            11.7 Other Indemnification Provisions. The foregoing indemnification
provisions  are in  addition  to,  and  not in  derogation  of,  any  statutory,
equitable, or common law remedy the Seller may have with respect to the Buyer or
the transactions contemplated by this Agreement.  Notwithstanding the foregoing,
each of the Seller and the  Shareholder  hereby agrees that it will not make any
claim for indemnification against any Person who is or was a director,  officer,
employee,  or agent of any of the Buyer,  Promega  and their  Affiliates  or was
serving at the  request  of any such  entity as a  partner,  trustee,  director,
officer,  employee,  or agent of another entity (each such Person,  a "Protected
Promega  Person")  (whether  such claim is for  judgments,  damages,  penalties,
fines, costs,  amounts paid in settlement,  losses,  expenses,  or otherwise and
whether  such  claim  is  pursuant  to any  statute,  charter  document,  bylaw,
agreement,   or  otherwise)  with  respect  to  any  action,  suit,  proceeding,
complaint, claim, or demand brought by the Seller against the Buyer or Promega.

                                   ARTICLE XII

                                   TERMINATION

            12.1 Rights to  Terminate.  This  Agreement may be terminated at any
time prior to the Closing only as follows:

              (a)    by mutual written  consent of the Seller,  the  Shareholder
                     and the Buyer;

              (b)    by the Buyer by giving written notice to the Seller and the
                     Shareholder  on or before March 22,  1999,  if the Buyer is
                     not satisfied with the results of its continuing  business,
                     legal and accounting due diligence of the Seller.

              (c)    by the Seller and the  Shareholder by giving written notice
                     to  the   Buyer  if  the   Buyer  is  in   breach   of  any
                     representation,  warranty or covenant  under this Agreement
                     (and  


                                      -43-


<PAGE>

                     neither the Seller nor the  Shareholder  are then in breach
                     of any representation, warranty or covenant);

              (d)    by the Buyer by giving written notice to the Seller and the
                     Shareholder if the Seller or the  Shareholder are in breach
                     of any  representation,  warranty  or  covenant  under this
                     Agreement  (and  the  Buyer is not  then in  breach  of any
                     representation, warranty or covenant); or

              (e)    by either the Buyer or the Seller  and the  Shareholder  by
                     giving  written  notice to the other parties if the Closing
                     shall not have occurred on or before May 15, 1999.

            Each party's right to termination hereunder is in addition to any of
the rights it may have hereunder or otherwise.

            12.2 Effects of Termination.  Notwithstanding any other provision of
this Agreement,  no termination of this Agreement shall release any party of any
Liabilities  arising  hereunder  for  any  pre-termination  breaches  hereof  or
intentional misrepresentations made herein.

                                  ARTICLE XIII

                                    GUARANTEE

            13.1  Guarantee  by  the   Shareholder.   The   Shareholder   hereby
irrevocably,  absolutely and unconditionally guarantees to the Buyer and Promega
(a) the  payment  of all  amounts  due and  payable  by the  Seller  under  this
Agreement  and each  other  agreement,  document  and  instrument  executed  and
delivered by the Seller in connection with the transactions contemplated by this
Agreement and (b) the  performance  of all agreements  and  undertakings  of the
Seller under this  Agreement and each other  agreement,  document and instrument
executed  and  delivered  by the  Seller  in  connection  with the  transactions
contemplated  by this  Agreement,  in each case strictly in accordance  with the
terms hereof or thereof.

            13.2 Guarantee by Promega.  Promega hereby  irrevocably,  absolutely
and unconditionally  guarantees to the Seller and the Shareholder the payment of
the Purchase  Price,  including the payment of  obligations  under the Note, the
performance of the Buyer's obligations under Article VII, the Buyer's obligation
to consummate the transactions  contemplated by this Agreement if the provisions
of Article VIII of this Agreement are satisfied,  the Buyer's  obligations under
the Lease and the Buyer's obligations under the Quality Assurance Agreement.


                                      -44-


<PAGE>

                                   ARTICLE XIV

                                   DEFINITIONS

            14.1 Certain Defined Terms. As used in this Agreement, the following
terms shall have the meanings  specified in this Section 14.1 unless the context
otherwise requires.

            "Adjustment Amount" has the meaning set forth in Section 2.1(a)(ii).

            "Affiliate"  has  the  meaning  set  forth  in  Rule  12b-2  of  the
regulations promulgated under the Securities Exchange Act.

            "Agreement" means this Asset Purchase  Agreement,  together with all
Exhibits and Schedules hereto, as amended,  restated,  supplemented or otherwise
modified from time to time in accordance with the terms hereof.

            "Applicable Rate" means 7% per annum.

            "Assignment,  Bill of Sale  and  Assumption  Agreement"  means  that
Assignment, Bill of Sale and Assumption Agreement, dated as of the Closing Date,
between  the  Seller  and the  Buyer,  in  substantially  the form of  Exhibit B
attached hereto.

            "Assumed Liabilities" has the meaning set forth in Section 3.1.

            "Benefit Plans" has the meaning set forth in Section 4.25(a).

            "Biogenex  License  Agreement" means that certain license  agreement
dated as of January 20, 1999, between the Seller and Biogenex, Inc.

            "Business"  has  the  meaning  set  forth  in the  recitals  to this
Agreement.

            "Business Combination" has the meaning set forth in Section 6.15.

            "Buyer"  has the meaning  set forth in the first  paragraph  to this
Agreement.

            "Buyer's Accountants" has the meaning set forth in Section 2.2(c).

            "Buyer's  Group  Health  Plan" has the  meaning set forth in Section
7.13.

            "Buyer's  Welfare  Plans" has the  meaning  set forth for in Section
7.13.

            "Closing" has the meaning set forth in Section 1.4.

            "Closing Balance Sheet" has the meaning set forth in Section 2.2(c).


                                      -45-


<PAGE>

            "Closing Date" has the meaning set forth in Section 1.4.

            "COBRA" has the meaning set forth in Section 4.25(d).

            "Code" means the Internal Revenue Code of 1986, as amended.

            "Commission"   means  the  United  States  Securities  and  Exchange
Commission.

            "Commission Filings" has the meaning set forth in Section 4.35.

            "Contracts" has the meaning set forth in Section 1.2(h).

            "Dispute Accountants" has the meaning set forth in Section 2.2(d).

            "Environmental  Claim"  means any and all  claims,  demands,  suits,
actions,  orders,  directives,  notices of  noncompliance  or violation,  liens,
investigations  or  administrative,  regulatory or judicial  proceedings  by any
Person  alleging   potential   liability  or  responsibility   for  enforcement,
penalties, fines, forfeitures, damages, losses, costs, costs for Remedial Action
taken,  governmental response costs, natural resource damages, property damages,
personal injury or bodily injury arising out of, based on or resulting from: (A)
the  presence,   use,   manufacture,   processing,   distribution,   production,
generation,   handling,   transport,  storage,  disposal,  labeling,  discharge,
release, threatened release, treatment,  control or cleanup of any Environmental
Material  at any  location;  or  (B)  circumstances  forming  the  basis  of any
violation,  or alleged  violation,  of any Environmental Law; or (C) any and all
claims by any person or Governmental  Authority  seeking damages,  contribution,
indemnification,  costs,  compensation or injunctive  relief  resulting from the
presence or Environmental Release of any Environmental Material.

            "Environmental  Law" means any Legal Requirement which relates to or
otherwise  imposes  liability,  obligations,  responsibility,  or standards with
respect to zoning, land use, pollution, or the restoration,  repair, remediation
or protection of natural resources,  human health or the environment  (including
ambient air, surface water, groundwater,  land surface, subsurface soil strata),
including without  limitation,  any Legal Requirement  relating to the presence,
use, manufacture,  processing,  distribution,  production, generation, handling,
transport,  storage, disposal, labeling, discharge, release, threatened release,
treatment, control or cleanup of any Environmental Material.

            "Environmental   Material"  means:  (A)  any  petroleum   substance,
petroleum product,  underground storage tank,  underground cistern,  radioactive
material,   asbestos  in  any  form  that  is  or  could  become  friable,  urea
formaldehyde  foam  insulation,   PCB-containing  Material;  (B)  any  Hazardous
Substance, Hazardous Material, Hazardous Waste or any other material, substance,
chemical,  waste,  contaminant or pollutant which is now or hereafter defined as
or  determined  to  be  hazardous,   extremely  hazardous,   toxic,   dangerous,
restricted,  or a nuisance,  or words of similar import, under any Environmental
Law; (C) any other material, substance, chemical, waste, contaminant,  pollutant
or exposure to which is now prohibited, limited or regulated by any Governmental
Authority or pursuant to any Environmental Law.


                                      -46-


<PAGE>

            "Environmental Permits" means all permits, licenses, authorizations,
certifications,  notices,  approvals or  authorizations  under any Environmental
Law.

            "Environmental  Release"  shall mean any release,  spill,  emission,
leaking,  injection,  deposit,  disposal,  discharge,   dispersal,  leaching  or
migration into the atmosphere, soil, surface water, groundwater or soil.

            "Equipment" has the meaning set forth in Section 1.2(f).

            "ERISA" means the Employee  Retirement  Income Security Act of 1974,
as amended.

            "Estimated  Net Book  Value"  has the  meaning  set forth in Section
2.2(a).

            "Excluded Assets" has the meaning set forth in Section 1.3.

            "Excluded Liabilities" has the meaning set forth in Section 3.2.

            "Final Net Book Value" has the meaning set forth in Section 2.2(a).

            "Financial Statements" has the meaning set forth in Section 4.9.

            "First Day" has the meaning set forth in Section 7.13.

            "GAAP" means United States generally accepted accounting  principles
as in effect from time to time.

            "Granada Leases" means, collectively, that certain Lease dated as of
February 27, 1990 between the Seller and Sueldo Associates, a California general
partnership, as amended, and that certain Revised and Restated Lease dated as of
March 1, 1990  between  the Seller and  Granada  Associates,  LLC, a  California
limited liability company, as amended.

            "Governmental  Authority"  means the government of the United States
of America and any other country, and any state, province, municipality or other
governmental  unit,  or  any  court,  agency,  board,  bureau,  instrumentality,
department or commission  (including any court or other  tribunal) of any of the
foregoing.

            "Hazardous  Material" means hazardous materials as defined under the
regulations adopted pursuant to the Hazardous Materials Transportation Act. Such
regulations appear at 49 C.F.R. Part 171, et seq.

            "Hazardous  Substance"  means hazardous  substances as defined under
the  Comprehensive  Environmental  Response,  Compensation and Liability Act, 42
U.S.C. ss.9601, et seq. and under comparable state laws.

            "Hazardous  Waste"  means  hazardous  waste  as  defined  under  the
Resource Conservation and Recovery Act, 42 U.S.C.ss.6901,  et seq.ss.144.60,  et
seq. and other comparable state laws.


                                      -47-


<PAGE>

            "Hired Employees" has the meaning set forth in Section 7.8.

            "Indemnifiable Damages" has the meaning set forth in Section 10.1.

            "Indemnitees" has the meaning set forth in Section 11.1.

            "Indemnitors" has the meaning set forth in Section 10.1.

            "Insurance" has the meaning set forth in Section 4.16(a).

            "Intellectual  Property" means, with respect to any Person,  any and
all United States and foreign  intellectual  property  owned or licensed by that
Person, including, without limitation, (i) all inventions (whether patentable or
unpatentable and whether or not reduced to practice),  all improvements thereto,
and all patents, patent applications (including international applications), and
patent    disclosures,    together   with   all   reissuances,    continuations,
continuations-in-part,  revisions,  extensions, and reexaminations thereof, (ii)
all trademarks,  service marks, trade dress, logos, trade names, brand names and
corporate names (including,  without limitation,  in the case of the Seller, the
name  "JBL  Scientific"  and  all  derivatives   thereof),   together  with  all
translations,  adaptations,  derivations, and combinations thereof and including
all goodwill  associated  therewith,  and all applications,  registrations,  and
renewals in connection therewith, (iii) all copyrightable works, all copyrights,
and all applications,  registrations, and renewals in connection therewith, (iv)
all mask works and all applications,  registrations,  and renewals in connection
therewith,   (v)  all  trade  secrets  and  confidential   business  information
(including ideas, research and development,  know-how,  formulas,  compositions,
manufacturing and production processes and techniques,  technical data, designs,
drawings,  specifications,   customer  and  supplier  lists,  pricing  and  cost
information,  and business and marketing plans and proposals), (vi) all computer
software owned or licensed by the Seller specifically including, but not limited
to,  software  developed  by or for  the  Seller  (including  data  and  related
documentation),  (vii) all other  proprietary  rights,  (viii)  all  copies  and
tangible embodiments thereof (in whatever form or medium). Intellectual Property
to be assigned includes, without limitation, the Intellectual Property set forth
in the Intellectual Property Assignments.

            "Intellectual Property Assignments" means those certain Intellectual
Property Assignments dated as of the Closing Date, between the Buyer and (i) the
Seller and (ii) the Shareholder,  in substantially the forms of Exhibits C-1 and
C-2  respectively,  as  the  same  may be  amended,  restated,  supplemented  or
otherwise modified from time to time.

            "Inventories" has the meaning set forth in Section 1.2(b).

            "IRS" means the Internal Revenue Service.

            "Knowledge"  means,  with respect to the Seller and the Shareholder,
the actual knowledge of Kenneth G. Kasses,  Thomas G. Burger, Robert E. Klem and
Lauren R. Brown after due inquiry.

            "Latest  Balance  Sheet" means the  unaudited  balance sheet for the
Business dated as of the Latest Balance Sheet Date and attached in Schedule 4.9.


                                      -48-


<PAGE>

            "Latest  Balance  Sheet  Date" has the  meaning set forth in Section
4.9.

            "Latest Fiscal Year End" has the meaning set forth in Section 4.9.

            "Lease" means that certain Lease  Agreement to be entered into as of
the Closing  Date,  between the Buyer and Granada  Associates,  LLC,  containing
terms  substantially  similar to the terms set forth on Exhibit D hereto, as the
same may be amended,  restated,  supplemented or otherwise modified from time to
time in accordance with its terms.

            "Leased  Property" shall mean the Real Estate,  as well as any other
real estate heretofore owned or used by Seller in the conduct of the Business.

            "Legal  Requirement"  means  any  and  all  statutes,  laws,  codes,
ordinances,  regulations,  rules, directives,  policy, orders, judgments, writs,
injunctions, rulings, decrees, bylaws or common law (whether presently in effect
or hereinafter  enacted,  adopted,  promulgated  or issued) of any  Governmental
Authority.

            "Liability"  means any  liability or  obligation  (whether  known or
unknown, whether asserted or unasserted, whether absolute or contingent, whether
accrued or unaccrued, whether liquidated or unliquidated,  and whether due or to
become due), including, without limitation, any liability for Taxes.

            "Lien" means any  mortgage,  pledge,  lien,  encumbrance,  charge or
other security interest of any kind.

            "Lipid License Agreement" means that certain Lipid License Agreement
dated  as of the  Closing  Date,  between  the  Shareholder  and the  Buyer,  in
substantially the form of Exhibit E attached hereto, as the same may be amended,
restated,  supplemented  or otherwise  modified  from time to time in accordance
with its terms,  pursuant to which the Buyer grants to the Seller an  exclusive,
royalty free license to use technology  pertaining to cationic lipids  described
in Attachment E-1 to the Lipid License Agreement.

            "Losses" has the meaning set forth in Section 10.1(a).

            "Material  Adverse  Effect" means a material  adverse  effect on the
Purchased Assets, operations, prospects or condition (financial or otherwise) of
the Business.

            "Net Book Value" has the meaning set forth in Section 2.2(b).

            "Nondisclosure  and  Noncompetition  Agreement"  means that  certain
Consulting and Noncompetition Agreement, dated as of the Closing Date, among the
Buyer,  the Seller and the Shareholder,  in substantially  the form of Exhibit F
attached hereto, as the same may be amended, restated, supplemented or otherwise
modified from time to time.

            "Note" means that certain $1,200,000 promissory note dated as of the
Closing Date made by the Buyer in favor of the Seller in substantially  the form
of  Exhibit G hereto,  as the same may be  amended,  restated,  supplemented  or
otherwise modified from time to time.


                                      -49-


<PAGE>

            "Notice of Claim" has the meaning set forth in Section 10.2.

            "Notice of Objection" has the meaning set forth in Section 10.2.

            "On-Site Contamination" has the meaning set forth in Section 6.23.

            "Operating  Accruals"  means the Assumed  Liabilities  specified  in
Section 3.1(a).

            "Ordinary  Course of Business" means the ordinary course of business
consistent   with  past  practice   (including  with  respect  to  quantity  and
frequency).

            "Owner" has the meaning set forth in the definition of  "Subsidiary"
set forth in Section 15.1.

            "PCB-containing Material" means polychlorinated biphenyls, including
PCB-laden lubricating or hydraulic oils or transformers or other equipment which
contain dielectric fluid containing polychlorinated biphenyls.

            "Pension Plan" has the meaning set forth in Section 4.25(a).

            "Permits" has the meaning set forth in Section 1.2(i).

            "Permitted Liens" means (a) any Lien for taxes that are not yet due,
(b)  any  carrier's,  warehouseman's,  mechanic's,  materialman's,  repairman's,
landlord's,  lessor's  or similar  statutory  lien  incidental  to the  ordinary
conduct of the  Business or (c) any  municipal  and zoning  ordinance,  recorded
easement, covenant or restriction that does not prohibit or materially interfere
with the present use, or materially affect the present value, of the Business or
the Purchased Assets.

            "Person"  means an  individual,  partnership,  corporation,  limited
liability company, firm, enterprise, business trust, joint stock company, trust,
unincorporated  association,  joint  venture,  Governmental  Authority  or other
entity of whatever nature.

            "Preliminary  Purchase  Price" has the  meaning set forth in Section
2.1(a).

            "Products Liability" has the meaning set forth in Section 4.26.

            "Promega"  has the meaning set forth in the fifth  paragraph  of the
recitals to this Agreement.

            "Promega 401(k) Plan" has the meaning set forth in Section 7.12.

            "Protected  Promega  Person"  has the  meaning  set forth in Section
11.7.

            "Protected  Shareholder Person" has the meaning set forth in Section
10.7.


                                      -50-


<PAGE>

            "Purchase Price" has the meaning set forth in Section 2.2(a).

            "Purchased Assets" has the meaning set forth in Section 1.2.

            "Quality  Assurance  Agreement" means that certain Quality Assurance
and  Quality  Control  Agreement,  between  the  Buyer and the  Shareholder,  in
substantially the form of Exhibit H attached hereto, as the same may be amended,
restated, supplemented or otherwise modified from time to time.

            "Real Estate" has the meaning set forth in Section 1.2(e).

            "Receivables" has the meaning set forth in Section 1.2(c).

            "Records"  means  books  of  account,   ledgers,   forms,   records,
documents,  files,  invoices,  lab notebooks,  archived batch records,  chemical
waste disposal records, vendor or supplier lists, plans and other data which are
necessary to or desirable for the  ownership,  use,  maintenance or operation of
the  Business  and  which are owned or used by any  Seller,  including,  without
limitation,  all blueprints and  specifications,  all Tax,  personnel,  payroll,
payroll tax and labor relations  records,  all  environmental  control  records,
environmental  impact  reports,  statements,   studies  and  related  documents,
handbooks,  technical  manuals  and data,  engineering  specifications  and work
papers, all pricing and cost information,  all sales records, all accounting and
financial records,  all sales and use Tax returns,  reports,  files and records,
asset history records and files,  all data entry and accounting  systems used to
conduct the day-to-day  operations of the Business,  all  maintenance and repair
records, all correspondence, notices, citations and all other documents received
from, sent to or in the Seller's  possession in connection with any Governmental
Authority  (including,  without limitation,  federal,  state, county or regional
environmental protection, air or water quality control,  occupational health and
safety,  land  use,  planning  or  zoning  and  any  alcohol,  beverage  or fire
prevention authorities), all plans, maps and surveys of the Real Estate, and all
plans and designs of buildings, structures, fixtures and equipment.

            "Remedial  Action" means any action taken or required to be taken as
a result of Environmental Law or by demand of Governmental Authority in response
to a known or suspected  condition in the  environment  (including  ambient air,
surface water, groundwater,  land surface or subsurface soil strata), including,
without  limitation,  sampling,  investigation,   monitoring,  remedial  action,
remediation,  removal, response,  restoration,  repair, replacement,  treatment,
clean-up and corrective action.

            "Restricted Interests" has the meaning set forth in Section 1.5(a).

            "Securities  Act"  means the  Securities  Act of 1993,  as  amended,
including any rules and regulations promulgated thereunder.

            "Securities Exchange Act" means the Securities Exchange Act of 1934,
as amended, including any rules and regulations promulgated thereunder.

            "Seller"  has the meaning set forth in the first  paragraph  to this
Agreement.


                                      -51-


<PAGE>

            "Seller Indemnifiable  Damages" has the meaning set forth in Section
11.1.

            "Seller Notice of Claim" has the meaning set forth in Section 11.2.

            "Seller  Notice of  Objection"  has the meaning set forth in Section
11.2.

            "Seller Purchased Assets" has the meaning set forth in Section 1.2.

            "Seller's Accountants" has the meaning set forth in Section 2.2(d).

            "Seller's 401(k) Plan" has the meaning set forth in Section 6.25 .

            "Seller's  Group  Health  Plan" has the meaning set forth in Section
6.24.

            "Seller's Welfare Plans" has the meaning set forth in Section 6.24.

            "Shareholder"  has the meaning set forth in the first  paragraph  to
this Agreement.

            "Shareholder  Purchased Assets" has the meaning set forth in Section
1.2.

            "Subsidiary"  means,  with  respect to any Person (the  "Owner") any
corporation or other Person of which  securities or other  interests  having the
power  to elect a  majority  of that  Person's  board of  directors  of  similar
governing  body,  or  otherwise  having  the power to direct  the  business  and
policies  of  that  Person  are  held  by  the  Owner  or  one  or  more  of its
Subsidiaries.  When used without reference to a particular  Person,  Subsidiary"
means a Subsidiary of the Seller.

            "Tax"  means any  federal,  state,  local or foreign  income,  gross
receipts,  license, payroll,  employment,  excise, severance, stamp, occupation,
premium,  windfall  profits,  environmental,   customs  duties,  capital  stock,
franchise, profits, withholding, social security, unemployment, disability, real
property,  personal property, sales, use, transfer,  registration,  value added,
alternative or add-on  minimum,  estimated or other tax of any kind  whatsoever,
including any interest, penalty or addition thereto, whether disputed or not.

            "Tax  Return"  means  any  return,  declaration,  report,  claim for
refund,  or  information  return or statement  relating to Taxes,  including any
schedule or attachment thereto, and including any amendment thereof.

            "Vehicles" has the meaning set forth in Section 1.2(g).

            14.2  Interpretation.  Unless otherwise expressly provided or unless
the  context  requires  otherwise,  (a)  all  references  in this  Agreement  to
Articles,  Sections,  Schedules  and Exhibits  shall mean and refer to Articles,
Sections,  Schedules  and  Exhibits of this  Agreement;  (b) all  references  to
statutes and related  regulations  shall include all  amendments of the same and
any  successor  or  replacement  statutes and  regulations;  (c) words using the
singular or plural  number also shall  include the plural and  singular  number,
respectively;  (d) references to "hereof,"  "herein," "hereby"


                                      -52-


<PAGE>

and similar terms shall refer to this entire Agreement  (including the Schedules
and Exhibits  hereto);  and (e) references to any Person shall be deemed to mean
and include the successors and permitted assigns of such Person (or, in the case
of a Governmental  Authority,  Persons  succeeding to the relevant  functions of
such Person).

            14.3 Other Terms. Except as otherwise  specifically  provided,  each
accounting term used herein shall have the meaning given to it under GAAP.


                                   ARTICLE XV

                                  MISCELLANEOUS

            15.1  Survival  of  Representations  and  Warranties.   All  of  the
representations  and warranties of the parties contained in this Agreement shall
survive the Closing hereunder to the extent provided in Sections 10.4 and 11.4.

            15.2 Benefit and  Assignment.  This Agreement  shall be binding upon
and  inure to the  benefit  of the  parties  hereto,  their  heirs,  successors,
assignees, and beneficiaries in interest; provided, however, that this Agreement
may not be assigned by the Seller or the  Shareholder  without the prior written
consent of the Buyer.

            15.3  Governing  Law.  This  Agreement  shall  be  governed  by  and
construed  in  accordance  with  the  internal  laws of the  State  of New  York
(regardless of such State's conflict of laws principles),  and without reference
to any rules of  construction  regarding the party  responsible for the drafting
hereof.

            15.4 Expenses.  Except as otherwise  herein  provided,  all expenses
incurred in connection with this Agreement or the  transactions  herein provided
for shall be paid by the party incurring such expenses and costs.

            15.5  Notices.  Every  notice  or other  communication  required  or
contemplated  by  this  Agreement  must  be in  writing  and  sent by one of the
following methods:  (i) personal  delivery,  in which case delivery is deemed to
occur the day of delivery;  (ii) certified or registered mail,  postage prepaid,
return receipt  requested,  in which case delivery is deemed to occur the day it
is officially  recorded by the U.S.  Postal Service as delivered to the intended
recipient;  or (iii) next-day delivery to a U.S. address by recognized overnight
delivery  service such as Federal  Express,  in which case delivery is deemed to
occur one  business  day  after  being  sent.  In each  case,  a notice or other
communication sent to a party must be directed to the address for that party set
forth below, or to another address designated by that party by written notice:


                                      -53-


<PAGE>

            (a)  If to the Buyer or Promega,

                 or both:                  Promega Corporation
                                           2800 Woods Hollow Road
                                           Madison, WI  53711-5399
                                           Attn:  General Counsel

                 With a copy to:           Tod B. Linstroth, Esq.

                                           Michael Best & Friedrich LLP
                                           One South Pinckney Street
                                           Suite 700
                                           Madison, WI 53703

            (b)  If to the Seller or the
                 Shareholder, or both:     c/o Genta Incorporated
                                           One Ledgemont Center
                                           99 Hayden Avenue, Suite 200
                                           Lexington, MA 02421
                                           Attn:  Kenneth G. Kasses, Ph.D.

                 With a copy to:           Monica Lord, Esq.
                                           Kramer Levin Naftalis & Frankel LLP
                                           919 Third Avenue
                                           New York, NY 10022

            15.6 Counterparts.  This Agreement may be executed simultaneously in
two or more counterparts,  each of which shall be deemed an original, but all of
which together shall constitute one and the same  instrument,  provided that all
such counterparts, in the aggregate, shall contain the signatures of all parties
hereto.

            15.7  Headings.   All  Section  headings  herein  are  inserted  for
convenience   only  and  shall  not  modify  or  affect  the   construction   or
interpretation of any provision of this Agreement.

            15.8 Amendment,  Modification and Waiver.  This Agreement may not be
modified,  amended or supplemented except by mutual written agreement of all the
parties hereto.  Any party may waive in writing any term or condition  contained
in this Agreement and intended to be for its benefit; provided, however, that no
waiver  by any  party,  whether  by  conduct  or  otherwise,  in any one or more
instances, shall be deemed or construed as a further or continuing waiver of any
such term or condition. Each amendment, modification, supplement or waiver shall
be in writing signed by the party or the parties to be charged.

            15.9 Entire Agreement. This Agreement and the Exhibits and Schedules
attached  hereto  represent the full and complete  agreement of the parties with
respect  to the  subject  matter  hereof and  supersede  and  replace  any prior
understandings  and  agreements  among the parties  with  respect to the subject
matter  hereof and no  provision or document of any kind shall be included in or
form a part of such agreement  unless signed and delivered to the other party by
the parties to be charged.


                                      -54-


<PAGE>

            15.10  Third-Party  Beneficiaries.  No third parties are intended to
benefit from this  Agreement,  and no  third-party  beneficiary  rights shall be
implied from anything  contained in this  Agreement,  except that each Protected
Shareholder   Person  and  each  Protected   Promega  Person  is  a  third-party
beneficiary under Sections 10.7 and 11.7, respectively.

            15.11  Publicity.  The Buyer and the Seller  agree that no publicity
announcements  or disclosures of any kind concerning the terms of this Agreement
or concerning  the  transactions  contemplated  hereby shall be made without the
mutual consent of the Buyer and the Seller, except to the extent that disclosure
is  required  by law or to  accountants,  counsel,  other  professionals  and to
lenders  on a  "need  to  know"  basis  who  similarly  agree  to  maintain  the
confidentiality  of  the  existence  of  and  terms  of the  Agreement  and  the
transactions contemplated thereby.

            15.12 Specific  Performance.  Each of the Buyer, Promega, the Seller
and the  Shareholder  acknowledges  and agrees that the other  parties  would be
damaged irreparably in the event any of the provisions of this Agreement are not
performed in  accordance  with their  specific  terms or otherwise are breached.
Accordingly,  each of the Buyer,  Promega, the Seller and the Shareholder agrees
that the other  parties shall be entitled to an  injunction  or  injunctions  to
prevent  breaches of the  provisions of this  Agreement and all  agreements  and
transactions contemplated hereby, and to enforce specifically this Agreement and
all  agreements  and  transactions   contemplated  hereby,  and  the  terms  and
provisions hereof or thereof in any action instituted in any court of the United
States or any state thereof having jurisdiction over the parties and the matter,
in  addition  to any  other  remedy  to which it may be  entitled,  at law or in
equity.

                            [SIGNATURE PAGE FOLLOWS]


                                      -55-


<PAGE>

                  [Signature Page to Asset Purchase Agreement]

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

                                              JBL ACQUISITION CORP.

                                              By:_______________________________
                                              Its:______________________________

                                              JBL SCIENTIFIC INCORPORATED

                                              By:_______________________________
                                              Its:______________________________

                                              GENTA INCORPORATED

                                              By:_______________________________
                                              Its:______________________________

            Promega  Corporation  hereby  executes this Agreement to confirm its
obligations under Section 13.2 of this Agreement.

                                              PROMEGA CORPORATION

                                              By:_______________________________
                                              Its:______________________________


<PAGE>

                                   EXHIBIT A-1

         [Form of Legal Opinion of Kramer Levin Naftalis & Frankel LLP]



                                      A-1-1


<PAGE>


                                   EXHIBIT A-2

          [Form of Legal Opinion of Sinsheimer, Schiebelhut & Baggett]


                                      A-2-1


<PAGE>

                                   EXHIBIT A-3

             [Form of Legal Opinion of Michael Best & Friedrich LLP]




                                      A-3-1

<PAGE>

                                    EXHIBIT B

           [Form of Assignment, Bill of Sale and Assumption Agreement]



                                       B-1



<PAGE>

                                   EXHIBIT C-1

                [Form of Seller Intellectual Property Assignment]




                                      C-1-1


<PAGE>

                                   EXHIBIT C-2

             [Form of Shareholder Intellectual Property Assignment]




                                      C-2-1


<PAGE>

                                    EXHIBIT D

                            [Summary of Lease Terms]

                                       D-1


<PAGE>

                                    EXHIBIT E

                        [Form of Lipid License Agreement]



                                       E-1



<PAGE>

                                    EXHIBIT F

              [Form of Nondisclosure and Noncompetition Agreement]




                                       F-1


<PAGE>

                                    EXHIBIT G

                                 [Form of Note]



                                       G-1



<PAGE>

                                    EXHIBIT H

                      [Form of Quality Assurance Agreement]



                                       H-1