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                                                                  Exhibit 10.13

CERTAIN INFORMATION HAS BEEN DELETED FROM THIS EXHIBIT AND FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR
CONFIDENTIAL TREATMENT UNDER RULE 24b-2.

                               LICENSE AGREEMENT

                                  regarding

                        US PATENTS ON TRANSPEPTIDATION

                                    between

                         PolyPeptide Laboratories A/S
                                 Herredsvejen 2
                                3400 Hillerod
                                   Denmark

                                     and

                               BioNebraska, Inc.
                              3820 NW 46th Street
                                   Lincoln
                               Nebraska 68524
                                     USA


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                              LICENSE AGREEMENT
                              (Transpeptidation)

THIS AGREEMENT is entered in to on the 17th day of February 1997, between:

(1)   PolyPeptide Laboratories A/S, a Danish company incorporated under the
      laws of Denmark, with its registered offices at Herredsvejen 2, 3400
      Hillerod, Denmark, hereinafter referred to as "the Licensor" and

(2)   BioNebraska, Inc., a company incorporated under the laws of the United
      States, with its registered offices at 3820 NW 46th Street, Lincoln,
      Nebraska 68524, USA, hereinafter referred to as "the Licensee".

WHEREAS:

A.    The Licensor has developed a patented invention on Transpeptidation
      relating to the manufacture and testing of pharmaceutical peptides;

B.    The parties wish to enter this Agreement for the purpose of licensing
      the use of the US Transpeptidation patents upon the terms and
      conditions hereafter contained.

The parties agree as follows:

1.    DEFINITIONS

      In this Agreement:

1.1   "the Patents" shall mean the US Patent No. 4,339,534 expiring July 13,
      1999 and US Patent No. 4,806,473 expiring February 21, 2006, both
      registered in the name of the Licensor, and all divisions,
      continuations, continuations in part, re-issues, renewals, extensions
      or editions to any such Patent.

1.2   "the Territory" shall mean United States of America

1.3   "the Patented Technology" shall mean the technology for the production
      and use of peptides and proteins produced with DNA recombinant
      technology as covered by the Patents and includes all matters required
      to be confidential according to Article 6.

1.4   "a Product" shall mean any pharmaceutical product comprised in whole or
      in part of peptides or proteins produced with the use of the Patented
      Technology.


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1.5   "controlling interest" shall mean with reference to a party hereto or
      an assignee the interest in that body of a person, firm, or
      corporation who or which:

      (i)    is able to exercise or is entitled to acquire control (whether
             direct or indirect) over the body's affairs and in particular
             (but without prejudice to the generality of the preceding words)
             if he or it possesses or is entitled to acquire the greater part
             of the issued share capital or voting power in the body or

      (ii)   in the event of the dissolution or liquidation of the body would
             be entitled to the greater part of the assets available for
             distribution among its shareholders.

1.6   "Net Sales" shall mean gross proceeds resulting from sales of a
      Product in the Territory by Licensee less:

      (i)    trade and/or cash discounts actually allowed and taken,

      (ii)   forwarding expenses, freight, postage and duties actually paid
             or allowed and taxes imposed on the seller with respect to such
             sales, and

      (iii)  credits for goods returned and any credit given for reduction in
             price.

1.7   Where the context so admits the singular includes the plural and vice
      versa.

1.8   The clause headings shall not form part hereof for the purpose of
      construction.

2.    GRANT OF RIGHTS

      In consideration of the fees and royalty payments hereinafter referred
      to, the Licensor hereby grants to the Licensee under the Patents, the
      Patented Technology and all other rights held by the Licensor an
      exclusive license to a restricted use of the Patented Technology,
      namely for the production and use of peptides and proteins produced
      with DNA recombinant technologies in the Territory. The Licensee shall
      not directly or indirectly use the Patents or Patented Technology for
      any purpose other than expressly granted hereunder, whereas the
      licensor retains its right to make use of the patents within the
      Territory for non-recombinant use.

3.    PAYMENTS

3.1   Fees

      Upon signing this Agreement, the Licensee will pay the Licensor a fee of
      [CONFIDENTIAL TREATMENT REQUESTED] for obtaining the exclusive license
      as described in Article 2. One year after having received the first
      regulatory approval for the marketing of a Product,


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      the Licensee shall pay to the Licensor a further fee of [CONFIDENTIAL
      TREATMENT REQUESTED].

3.2   Royalty

      The Licensee agrees to pay to the Licensor royalties for the rights
      granted to it hereunder at the rate of [CONFIDENTIAL TREATMENT
      REQUESTED] of the Net Sales by the Licensee of a Product until the last
      of the Patents expires. Forty five (45) days after the end of each
      calendar quarter, the Licensee shall furnish to the Licensor a
      calculation of Net Sales and the royalties payable hereunder for such
      calendar quarter and shall accompany each such report with the payment
      of royalties then due. Calendar quarters shall be the periods ending on
      March 31, June 30, September 30 and December 31. The Licensor shall
      have the right, through its duly authorised representatives, and at its
      expense, to examine the books and records of the Licensee during
      reasonable business hours for the purpose of verifying the correctness
      of the calculation of Net Sales and royalties payable.

3.3   Currency

      Fees and Royalties accrued pursuant to this Agreement shall be payable
      to the Licensor in US Dollars. If direct remittance to the Licensor in
      US Dollars of such fees and royalties is not lawful or practicable,
      payment thereof shall be made by deposit, within the period provided
      for in Section 3.1, - upon execution of the Agreement and 1 year after
      occurrence of the first regulatory approval - and Section 3.2 - 45 days
      after the end of each calendar quarter.

4.    TRANSFER OF PATENTED TECHNOLOGY

      The Licensor shall promptly disclose to the Licensee all particulars
      and details of the Patented Technology sufficient for the Licensee to
      use it for the production and use of peptides and proteins produced
      with DNA recombinant technology.

5.    CONFIDENTIAL INFORMATION

      During the continuance of this Agreement and at all times thereafter
      the Licensee shall (except to fulfil the purposes of this Agreement)
      keep confidential the Patented Technology, the improvements and
      information related thereto and shall not disclose or use any part of
      it and the Licensee shall (except to fulfil the purposes of this
      Agreement) keep confidential and shall not disclose or use any
      information received by it from the Licensor whether under this
      Agreement or otherwise (except to the extent that such information is
      published by the Licensor or is contained in a published patent
      specification or is generally known otherwise than by a breach of this
      Agreement) and shall ensure by securing and enforcing suitable
      contractual provisions that its employees and all other persons or
      companies to whom such information is communicated shall be similarly
      bound.


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6.    PATENT INFRINGEMENTS

(a)   If either of the parties hereto shall come to know of any infringement
      or threatened infringement of the Patents then it shall immediately
      inform the other party thereof and both parties shall discuss what
      action shall be taken.

(b)   Should either party decide for any reason that it is not willing to
      take legal proceedings in respect of such infringement then the other
      party may at its own expense take any such action as it considers
      desirable and the inactive party shall on reimbursement of its expenses
      lend its name and give the party taking such action all such assistance
      whether legal or technical as such other party requests of it.

7.    ASSIGNMENT

      Neither the Licensor nor the Licensee may assign this Agreement except:

      (a)   to an assignee in which that party has a controlling interest; or

      (b)   with the consent of the other party which consent shall not be
            unreasonably withheld.

8.    WARRANTIES

8.1   Exclusivity

      The Licensor warrants to the Licensee that the Licensor will not use
      the Patented Technology for the production and use of peptides and
      proteins produced by nonrecombinant technologies in the Territory, nor
      that the Licensor has granted or will grant any other license for the
      herein described use of the Patented Technology during the term of this
      Agreement.

8.2   Restricted Use

      The Licensee warrants to the Licensor that the Licensee will not use
      the Patented Technologies for any other purpose than for peptides and
      proteins produced with DNA recombinant technologies, and especially
      will not use the Patented Technologies for the product Calcitonin.

9.    PERIOD OF AGREEMENT

      Subject to the provisions of Clause 10 hereof, this Agreement shall
      continue for the life of the last Patent to expire.

10.   TERMINATION

      This Agreement may be terminated at any time in any of the following
      ways:


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      (a)   if either of the parties shall become insolvent or shall have a
            receiver or trustee appointed in charge of the whole or any part
            of its assets or shall enter into liquidation (other than for the
            purposes of reorganisation), then the other party may by notice in
            writing served upon it terminate this Agreement with immediate
            effect.

      (b)   if either of the parties shall commit a material breach of its
            obligations under this Agreement, the other may send to it notice
            in writing specifying the breach complained of and calling upon
            it to remedy the same within a specified period of not less than
            ninety days, and if the party in default shall not have remedied
            the breach within the said period, then the party serving the
            notice may terminate this Agreement by a further 14 days' notice
            in writing served upon the party in default.

11.   NOTICES

      Any notice or other communication authorised or required to be given
      hereunder or for the purposes hereof shall be deemed to be sufficiently
      given to either party if left at or forwarded by registered post,
      recorded delivery service, or facsimile addressed to such party at its
      last known address or its registered office and every notice or other
      such communication shall be deemed to have been received and given at
      the time when in the ordinary course of transmission it would have been
      delivered at the address to which it was sent.

12.   LAW

      This Agreement shall in all respects be governed by the laws of
      England.

13.   ARBITRATION

      All disputes between the parties relating to this Agreement, including
      its interpretation that cannot be settled amicably by the parties,
      shall be referred to and finally resolved by arbitration under the
      Rules of the London Court of International Arbitration in England,
      which Rules are deemed to be incorporated by reference to this Article.


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PolyPeptide Laboratories, A/S          BioNebraska, Inc.

/s/ Erik Lorentsen                     /s/ Thomas R. Coolidge
---------------------------------      -------------------------------
Hillerod, February 17, 1997            Falls Village, 2/27 1997
General Manager                        Chairman of the Board and CEO


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