Document:

<PAGE>   1
                                                                   EXHIBIT 10.18

                                   ADDENDUM TO
THE BUSINESS INFORMATION PRODUCTS DEVELOPMENT AND DISTRIBUTION AGREEMENT AND
DATA ANALYSIS PRODUCTS DEVELOPMENT AND DISTRIBUTION AGREEMENT, AUGUST 16, 2000

Amersham Pharmacia Biotech, Inc., and InforMax, Inc., hereby agree to extend the
deadlines within Sections 2.2, 2.3, 2.5, 5.8a of the above mentioned agreements
by an additional 100 days (from February 12, 2001 to May 23, 2001). Otherwise
the agreements remain in full force and effect. If in agreement of the
foregoing, please sign below:

Amersham Pharmacia Biotech, Inc.                Informax, Inc.

By:  /s/ ANDREW WHITELEY                        By:  /s/ JAMES E. BERNSTEIN
   -----------------------------------             -----------------------------
Name: ANDREW WHITELEY                           Name: JAMES E. BERNSTEIN
     ---------------------------------               ---------------------------
Title: VP Bioinformatics                        Title: President
      --------------------------------                --------------------------
Date: Feb. 7th 2001                             Date: Feb. 9th 2001
      --------------------------------               ---------------------------<PAGE>   1
                                                                   EXHIBIT 10.24

                              EMPLOYMENT AGREEMENT

THIS EMPLOYMENT AGREEMENT between JOHN MARSHALL GREEN, residing at 4101 Fordham
Road NW, Washington, DC 20016 ("Employee"), and INFORMAX, INC., a Delaware
corporation with offices at 6010 Executive Boulevard, 10th floor, North
Bethesda, Maryland 20852 ("InforMax") is entered into as of O2 MARCH 2001, (the
"Effective Date") and sets forth the terms and conditions of Employee's
continued employment by InforMax.

                                   WITNESSETH

        WHEREAS, Employee intends to be employed by InforMax as a Senior Vice
President, and Chief Financial Officer of InforMax under the terms and
conditions set forth herein

        NOW THEREFORE, in consideration of the premises and of the mutual
covenants and conditions contained in this Agreement, the parties hereto,
intending to be legally bound, agree as follows:

1.      EMPLOYMENT. InforMax hereby employs Employee and Employee hereby
accepts employment with InforMax upon the terms and conditions set forth in this
Agreement. Employee's principal titles and responsibilities shall be that of
Senior Vice-President, and Chief Financial Officer reporting to the Chief
Executive Officer ("CEO"), and will work closely with the Chief Operating
Officer ("COO"). Employee shall perform such reasonable duties consistent with
these titles as shall be assigned to him from time to time by the COO and/or the
CEO of the InforMax, with the CEO having superiority. INITIAL ASSIGNMENT WILL
INCLUDE ALL FINANCIAL FUNCTIONS, HUMAN RESOURCES AND ADMINISTRATION (E.G.
INFORMATION SERVICES, FACILITIES, ETC.)

        2.      TERM OF AGREEMENT. The term of this Agreement shall commence on
the Effective Date, and, except as otherwise provided herein, shall terminate on
Dec 31, 2003. The Agreement shall automatically renew for additional terms of
one (1) year unless, not less than ninety (90) days before the next termination
date of the Agreement, either party provides notice in writing to the other that
it does not intend to renew the Agreement

        3.      COMPENSATION.

                (a)     Base Salary. InforMax shall pay, and Employee shall
accept, during the term of this Agreement, as compensation for services rendered
hereunder an annual salary of $215,000 payable in semi-monthly installments. THE
EMPLOYEE WILL HAVE AN ANNUAL PERFORMANCE REVIEW AND ADJUSTMENT TO THE BASE
SALARY WILL BE MADE AT LEAST ANNUALLY IN CONJUNCTION WITH THE ANNUAL PERFORMANCE
REVIEW. In addition, Employee will be eligible for bonuses commensurate with
performance of 5O% of base salary SUBJECT TO APPROVAL BY THE

<PAGE>   2

BOARD. THE BONUS WILL BE BASED ON MUTUALLY DEVELOPED OBJECTIVES AND COMPANY
PERFORMANCE.

                (b)     Stock Options. Employee shall be granted options to
purchase 225,000 shares of common stock at the price of Informax stock at the
close of trading on March 1, 2001. 28,125 shares shall vest on SEPTEMBER 2,
2001. The remaining 196,875 options shall vest monthly at the rate of 4,687
shares per month over FORTY-TWO months commencing OCTOBER 2, 2001. THE FINAL
MONTH VESTING WILL INCLUDE THE ADDITIONAL OPTION REQUIRED TO EQUAL 225,000
GRANTED OPTIONS. InforMax's Equity Incentive Compensation Plan shall govern all
options granted. All options granted and stock obtained from exercise of said
options shall be governed by the Company's Insider Trading Policy.

                (c)     Benefit Plans. Employee shall be entitled to participate
in such benefit plan(s) of InforMax now in existence or which may hereafter
during the term of this Agreement become effective for senior executives of
InforMax. Nothing in this Section 3(c) shall be deemed to prevent InforMax from
altering or abolishing any of such plans or benefits provided that all such
senior executives are treated equally.

                (d)     Vacation. During the term of this Agreement, Employee
shall be entitled ANNUALLY to three (3) weeks paid vacation in accordance with
the established policy of InforMax. Employee also shall be entitled to all paid
holidays and personal days given by InforMax.

                (e)     Automobile. The Company shall provide $500 per month
toward a leased automobile for use by the Employee.

                (e)     Expenses. InforMax shall promptly pay or reimburse
Employee upon submission of vouchers or receipts for all reasonable
out-of-pocket expenses for entertainment, travel, meals, hotel accommodations,
CELLULAR TELEPHONE, HIGH SPEED COMPUTER ACCESS, and the like, incurred by him
that are reasonably related to the performance of his duties.

                (f)     Withholding. Employee acknowledges that InforMax may
withhold from amounts payable to Employee under this Agreement with respect to
certain income, unemployment and social security taxes required to be withheld
from the wages of employees under applicable Federal, State, and local law. No
other taxes, fees, impositions, duties or other charges of any kind shall be
deducted or withheld from amounts payable hereunder, unless otherwise required
by law or agreed to by Employee.

<PAGE>   3

        4.      TERMINATION OF EMPLOYMENT. Notwithstanding any provisions herein
to the contrary, Employee's employment with InforMax may be terminated prior to
the completion of the term described in Section 2 of this Agreement, subject to
the following terms and conditions:

                (a)     Termination for Cause. InforMax may terminate Employee's
employment at any time for Cause. For the purpose of this Agreement, the term
"Cause" shall mean Employee's (1) willful misconduct; (2) gross negligence in
the performance of his PRINCIPAL duties for more than five (5) days after
receiving written notice from InforMax on the grounds of purported failure to
perform and corresponding failure by Employee to cure such breach within thirty
(30) days of written notice; (3) willful violation of any law, rule or
regulation (other than traffic violations or similar offenses) or (4) material
breach of any provision of this Agreement. THE EMPLOYEE SHALL ALSO HAVE 30 DAYS
FROM THE DATE OF TERMINATION TO EXERCISE ALL VESTED OPTIONS.

                (b)     Termination Without Cause upon a Change of Control.
InforMax shall pay Employee a sum equal to his annual base salary plus A BONUS
(EQUAL TO A GUARANTEED 12-MONTH PRO-RATED SHARE OF THE PREVIOUS FISCAL YEAR'S
PERFORMANCE BONUS) at the time of a "Change In Control" upon termination by
InforMax of Employee's employment without Cause within 180 days of a "Change in
Control". For the purposes of this Section a "Change of Control" of the Company
shall be deemed to have occurred if (i) any person or entity other than a person
currently a beneficial owner of the Company's securities becomes, after the date
hereof, the beneficial owner of securities of the Company representing 50% of
more of the combined voting power of the Company's then outstanding securities,
or (ii) the Company sells all or substantially all or substantially all of the
assets of the Company. ALL GRANTED AND UNVESTED OPTIONS SHALL VEST AT A CHANGE
IN CONTROL AS DEFINED ABOVE. THE EMPLOYEE SHALL ALSO HAVE 30 DAYS FROM THE DATE
OF TERMINATION TO EXERCISE ALL VESTED OPTIONS.

                (c)     Termination Without Cause other than upon a Change of
Control. InforMax shall pay Employee a lump-sum cash payment in an amount equal
to fifty percent (50%) of his annual salary plus fifty percent (50%) of his
bonus (EQUAL TO A GUARANTEED 12-MONTH PRO-RATED SHARE OF THE PREVIOUS FISCAL
YEAR'S PERFORMANCE BONUS) for the previous twelve (12) months upon termination
by InforMax of Employee's employment without cause other than as provided in
Section 4(b) above. The severance payment shall be paid to Employee in cash as
promptly as practicable, but in no event later than thirty (30) days following
the termination of his employment. THE EMPLOYEE SHALL HAVE 30 DAYS FROM DATE OF
TERMINATION TO EXERCISE ALL VESTED OPTIONS. Employee's options will cease
vesting on the date of termination.

                (d)     Termination by Employee for Breach by InforMax. In the
event that InforMax breaches this Agreement in any material respect and fails to
cure the breach within thirty (30) days of written notice, Employee may
terminate his employment. In the event of such termination, InforMax shall pay
Employee a lump-sum cash payment in an amount equal to fifty percent (50%) of
his annual salary plus fifty percent (50%) of his bonus (EQUAL TO A GUARANTEED

<PAGE>   4

12-MONTH PRO-RATED SHARE OF THE PREVIOUS FISCAL YEAR'S PERFORMANCE BONUS) for
the previous twelve (12) months. The severance payment shall be paid to Employee
in cash as promptly as practicable, but in no event later than thirty (30) days
following such termination. THE EMPLOYEE SHALL HAVE 30 DAYS FROM DATE OF
TERMINATION TO EXERCISE ALL VESTED OPTIONS.

                (e)     Voluntary Termination by Employee without Cause. Any
termination of Employee's employment by resignation, retirement or any other
action of Employee for any reason other than as set forth in Section 4(d) shall
be deemed to be a "Voluntary Termination." Employee shall give InforMax thirty
(30) days notice of a Voluntary Termination.

                (f)     Payment Upon Termination For Cause or Voluntary
Termination. InforMax's obligation to pay Employee any and all compensation and
benefits shall cease in the event of a Termination for Cause or a Voluntary
Termination, and InforMax shall not be liable for any further payments to
Employee hereunder except for accrued salary, accrued vacation days,
reimbursement of appropriate expense vouchers, applicable indemnification
obligations and other benefit continuation obligations imposed by law.

        5.      DEVOTION OF TIME. Except for vacations as provided herein and
absences due to temporary illness or family emergencies, Employee agrees to
devote his business time, best efforts and undivided attention and energies
during the term of this Agreement to the performance of his duties and to
advance InforMax's interests. During the term of this Agreement, Employee shall
not, without the prior written approval of the Board of Directors, or its
designee, be engaged in any other business activity which, in the reasonable
judgment of the Board of Directors, conflicts with the duties of Employee,
whether or not such business activity is pursued for gain, profit, or other
pecuniary advantage; but this restriction shall not be construed as preventing
Employee from investing his assets in such form or manner as will not require
the performance of services of Employee in the operations of the affairs of the
enterprises or companies in which said investments are made. Notwithstanding the
foregoing, services, which are neither substantial nor significant, individually
or in the aggregate, shall be permitted with respect to investments of Employee
provided that they shall not have an adverse effect on Employee's duties
hereunder.

        6.      NON-COMPETITION. Employee agrees that during the period of
Employee's employment by InforMax and for a period of one (1) year after
termination of this Agreement for any reason

                        (i)     Employee will not solicit business from or
        perform work for any of InforMax's past or present clients, or any of
        InforMax's prospective clients to whom InforMax has made a written
        proposal within six (6) months prior to any termination of Employee's
        employment with InforMax, either directly or indirectly, for the benefit
        of anyone other than InforMax, or participate or assist in any way in
        the solicitation of business from or performance of work for any such
        clients, as an independent contractor or consultant to any other entity
        unless the business being solicited or the work being performed is not
        the Same Business as that in which InforMax is engaged. As used in

<PAGE>   5

                        (ii)    Employee will not divert, solicit, or pirate on
        Employee's behalf, or on the behalf of any other employer, person, or
        entity, any employee of InforMax, or directly or indirectly induce or
        attempt to influence any such employee to leave InforMax's employment.

                        (iii)   Employee will not, directly or indirectly, on
        Employee's behalf or in the service or on behalf of others, render or be
        retained to render services whether as an officer, partner, trustee,
        consultant, or employee, for any business engaged in the Same Business
        as InforMax including but not limited to any customer of InforMax for
        whom Employee has provided services during Employee's employment with
        InforMax, unless the same is provided solely to that portion or unit of
        any such business that is not engaged in the Same Business.

                        (iv)    The business of InforMax is international in
        scope and the restrictions of this paragraph shall accordingly apply
        worldwide ONLY TO THE EMPLOYEE IF BEING ENGAGED IN THE ACTIVITIES
        DESCRIBED IN 6 i - 6 iii ABOVE FOR AND ON BEHALF OF ENTITIES IS THE SAME
        BUSINESS AS INFORMAX.

        7.      NONDISCLOSURE OF PROPRIETARY INFORMATION. Both during and after
the term of this Agreement, Employee agrees to preserve and protect the
confidentiality of Proprietary Information as defined in Section 8 below. In
addition, Employee will not (i) disclose or disseminate Proprietary Information
to any third party, including employees of InforMax without a need to know, or
(ii) use Proprietary Information for his own benefit or for the benefit of any
third party. If Employee receives information with uncertain confidentiality, he
agrees to treat the information as Proprietary Information until management has
verified to him that such information is neither confidential nor proprietary.

        8.      DEFINITION OF PROPRIETARY INFORMATION. Proprietary Information
is defined as information regarding InforMax's current and planned business
activities, including (i) information which relates to InforMax's actual or
anticipated products, software, research inventions, processes, techniques,
designs or other technical data; (ii) information regarding administrative,
financial or marketing activities of InforMax; (iii) information received from
InforMax clients and other third parties; and (iv) any materials or documents
containing any of the above information. Proprietary Information does not
include information, which is or becomes publicly available without a breach of
this Agreement by Employee or any information that the Employee POSSESSES
INDEPENDENT OF HIS RELATIONSHIP WITH INFORMAX.

        9.      RETURN OF PROPRIETARY INFORMATION. Upon termination of his
employment with InforMax, Employee agrees to deliver to InforMax all documents
and other tangibles including diskettes and other electronic or other storage
media containing Proprietary Information.

        10.     TRADE SECRETS. Employee understands and agrees that the
covenants, restrictions and prohibitions against disclosure of Proprietary
Information set forth in this Agreement are in

                                        5

<PAGE>   6

addition to, and not in lieu of, any rights or remedies which InforMax may have
available pursuant to the laws of any jurisdiction or at common law to prevent
disclosure of trade secrets or proprietary information, and the enforcement by
InforMax of its rights and remedies pursuant to this Agreement shall not be
construed as a waiver of any other rights or available remedies which it may
possess in law or equity absent this Agreement.

        11.     OWNERSHIP OF WORKS. During the time Employee is employed by
InforMax, InforMax shall own all rights, including all trade secrets and
copyrights, in and to the following works created by Employee whether created on
InforMax's premises or at some other location: (i) works which relate to or are
derived from the actual or anticipated business of InforMax and (ii) works which
result from or are derived from any task assigned to Employee or work performed
by Employee for InforMax (collectively, the "Works"). InforMax shall own such
Works even if created outside normal working hours and regardless of whether
Employee's own equipment or InforMax's equipment was used to create the Works.
Such Works shall include program codes and documentation. To the extent that any
such Works do not qualify as works made for hire under U.S. copyright law, this
Agreement will constitute an irrevocable assignment by Employee to InforMax of
the ownership of, and all rights of copyright in, such Works. Employee agrees to
give InforMax or its designees all assistance reasonably required to perfect
such rights provided that following termination of this Agreement, InforMax
shall reimburse Employee for his reasonable time and expense in assisting with
such matters.

        12.     INVENTIONS. If Employee individually or jointly makes or
conceives of any invention, technique, process, or other know-how, whether
patentable or not, in the course of performing services for InforMax, which
relates in any manner to the actual or anticipated business of InforMax or
results from any task assigned to Employee or work performed by Employee for
InforMax (collectively, "Inventions"), Employee will and hereby does assign to
InforMax his entire right, title and interest in such Inventions. Employee will
disclose any such Inventions to an officer of InforMax and will, upon request,
promptly sign a specific assignment of title to InforMax, and do anything else
reasonably necessary to enable InforMax to secure patents, trade secret or any
other proprietary rights in the United States or foreign countries, provided
that following termination of this Agreement, InforMax shall reimburse Employee
for his reasonable time and expense in assisting with such matters. Any
Inventions Employee has made or conceived before the effective date of this
Agreement are listed and described on Schedule A attached hereto. These items
are excluded from this Agreement.

        13.     INDEMNIFICATION. InforMax shall indemnify and hold harmless
Employee in his capacity as an officer as provided in the certificate of
incorporation and by-laws of InforMax, as amended from time to time. This
provision shall in no manner limit InforMax's right to amend its certificate of
incorporation or by-laws.

        14.     ASSIGNABILITY. This Agreement and all rights hereunder are
personal to Employee and shall not be assignable except in accordance with the
laws of descent and distribution, and any purported assignment in violation
thereof shall not be valid or binding on InforMax. This

<PAGE>   7

Agreement, however, shall inure to the benefit of, and be binding upon each
successor of InforMax, whether resulting from a merger or consolidation or to
the recipient of all or substantially all of the assets of InforMax (and such
successor shall thereafter be deemed the same as InforMax for purposes of this
Agreement). This Agreement shall in no way restrict InforMax's right to merge,
consolidate, sell all or substantially all of its assets or engage in any
business combination or other transaction of any nature.

        15.     ENTIRE AGREEMENT. This Agreement, including any Schedule A,
supersedes and replaces any and all present, written or oral, agreements of
employment between the parties hereto, and all such agreements are hereby deemed
canceled, revoked, and of no further force or effect.

        16.     ACKNOWLEDGMENT. The restrictions contained in Section 6 of this
Agreement are considered reasonable by Employee and InforMax, and it is the
desire of both parties that such restrictions and the other provisions of this
Agreement be enforced to the fullest extent permissible under the laws and the
public policies applied in each jurisdiction in which enforcement is sought.
Accordingly, in the event that any such restriction or provision shall be found
to be void or invalid but would be valid if some part thereof were deleted or
the period or area of application reduced, such restriction or provisions shall
apply with such modification as shall be necessary to make it valid and
effective. A deletion resulting from any adjudication shall occur only with
respect to the operation of the provision or a portion thereof affected in the
particular jurisdiction in which such adjudication is made, and each court or
other body having jurisdiction with respect to the enforcement of the provisions
of Section 6 of this Agreement are hereby empowered to modify by reduction,
rather than deletion, the time periods or other restrictions referred to
therein.

        17.     MODIFICATION. This Agreement constitutes the whole agreement of
employment of Employee by InforMax and there are no terms other than those
stated herein. No variation hereof shall be deemed valid unless in writing and
signed by the parties hereto, and no discharge of the terms hereof shall be
deemed valid unless by full performance by the parties hereto and by a writing
signed by the parties hereto. No waiver by either party of any provision or
condition of this Agreement by him or it to be performed shall be deemed a
waiver of similar or dissimilar provisions and conditions at the same time or
any prior or subsequent time.

        18.     NOTICES. Any notice, statement, report, request or demand
required or permitted to be given by this Agreement shall be in writing, and
shall be sufficient if addressed and sent by certified mail, return receipt
requested, to the parties at the addresses set forth above or at such other
place that either party may designate by notice to the other.

        19.     EQUITABLE RELIEF/PAYMENT OF FEES. The parties to this Agreement
agree that each of them shall be entitled, in addition to any other remedies
they may have under this Agreement, at law, or otherwise, to immediate
injunctive and other equitable relief to prevent or

<PAGE>   8

        19.     EQUITABLE RELIEF/PAYMENT OF FEES. The parties to this Agreement
agree that each of them shall be entitled, in addition to any other remedies
they may have under this Agreement, at law, or otherwise, to immediate
injunctive and other equitable relief to prevent or curtail any breach of this
Agreement. Each party agrees to indemnify the other party for all reasonable
costs.

        20.     GOVERNING LAW. This Agreement shall be governed by the laws of
the State of Maryland (regardless of the laws that might otherwise govern under
applicable principles or conflicts of law) as to all matters, including but not
limited to matters of validity, construction, effect, performance and remedies.

        21.     COUNTERPARTS. This Agreement may be executed in counterparts,
each of which shall be deemed an original, but which together shall constitute
one and the same instrument.

        23.     LIMITED AGREEMENT. This Agreement is intended by the parties to
govern only those rights and obligations described herein, and it is not the
parties' intent to abrogate any other rights in favor of Employee or InforMax
provided under Federal or State Law.

        IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date set forth above.

                                      InforMax, Inc.

                                      By:    /s/ JAMES BERNSTEIN
                                             --------------------------------
                                             James Bernstein
                                             President

                                      Employee:
                                                 /s/ JOHN MARSHALL GREEN 2/28/01
                                                 -------------------------------
                                                 John Marshall Green

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00022-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00022-of-00352.parquet"}]]