STOCK PURCHASE AGREEMENT BY AND AMONG COMMONWEALTH BIOTECHNOLOGIES, INC., PHARMAUST LIMITED AND PHARMAUST CHEMISTRY LTD. DATED NOVEMBER 24, 2006

Exhibit 99.1

STOCK PURCHASE AGREEMENT

BY AND AMONG

COMMONWEALTH BIOTECHNOLOGIES, INC.,

PHARMAUST LIMITED

AND

PHARMAUST CHEMISTRY LTD.

DATED

NOVEMBER 24, 2006

TABLE OF CONTENTS

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STOCK PURCHASE AGREEMENT

THIS STOCK PURCHASE AGREEMENT (this " Agreement ") is entered into as of November 24, 2006, by and between COMMONWEALTH BIOTECHNOLOGIES, INC. , a Virginia corporation (the " Buyer "), PHARMAUST LIMITED , an Australian limited company (the " Parent "), and PHARMAUST CHEMISTRY LTD , an Australian limited company (the "Seller"). The Buyer, the Seller and the Parent are referred to collectively herein as the " Parties ". The Seller owns all of the outstanding capital stock of MIMOTOPES PTY LTD , an Australian proprietary limited company (the " Target ").

WHEREAS , the Target is in the business of developing high quality research-grade peptide products and applications for the drug discovery industry;

WHEREAS , the Target is a wholly-owned subsidiary of the Seller;

WHEREAS , the Seller is a wholly-owned subsidiary of the Parent;

WHEREAS , the Buyer is in the business of providing analytical and synthetic chemistries and biophysical analysis technologies to the global biotechnology industry, academic institutions, government agencies and pharmaceutical companies;

WHEREAS , the Buyer desires to acquire the outstanding capital stock of the Target from the Buyer pursuant to the terms of this Stock Purchase Agreement; and

WHEREAS , the Parent is willing to enter into this Stock Purchase Agreement solely for the purposes described herein.

NOW , THEREFORE , in consideration of the premises and the mutual promises herein made, and in consideration of the representations, warranties, and covenants herein contained, the Parties agree as follows.

1 . Definitions .

" A&S " means Anderson & Strudwick, Incorporated.

" Adverse Consequences " means all actions, suits, proceedings, hearings, investigations, charges, complaints, claims, demands, injunctions, judgments, orders, decrees, rulings, damages, dues, penalties, fines, costs, reasonable amounts paid in settlement, liabilities, obligations, taxes, liens, losses, expenses, and fees, including court costs and reasonable attorneys’ fees and expenses.

" Affiliate " means a person that directly or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, the person specified.

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" Australian Dollars " and the symbol " A$ " shall mean sums of money in the currency of Australia.

" Buyer " has the meaning set forth in the preface above.

" Closing " has the meaning set forth in Section 2(c) below.

" Closing Date " has the meaning set forth in Section 2(c) below.

" Confidential Information " means any information concerning the businesses and affairs of the Target that is not already generally available to the public.

" Corporations Act " means the Corporations Act 2001 (Commonwealth).

" COTS " has the meaning set forth in Section 4(1)(iii).

" Disclosure Schedule " has the meaning set forth in Section 4 below.

" Environmental, Health, and Safety Requirements " shall mean all federal, state, local and foreign statutes, regulations, ordinances and similar provisions having the force or effect of law, all judicial and administrative orders and determinations, and all common law concerning public health and safety, worker health and safety, and pollution or protection of the environment, including without limitation all those relating to the presence, use, production, generation, handling, transportation, treatment, storage, disposal, distribution, labeling, testing, processing, discharge, release, threatened release, control, or cleanup of any hazardous materials, substances or wastes, chemical substances or mixtures, pesticides, pollutants, contaminants, toxic chemicals, petroleum products or byproducts, asbestos, polychlorinated biphenyls, noise or radiation.

" Financial Statements " has the meaning set forth in Section 4(f) below.

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

" GST " means the Australian Goods and Services Tax.

" Income Tax " means any federal, state, local, or foreign income tax, including any interest, penalty, or addition thereto, whether disputed or not.

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

" Indemnified Party " has the meaning set forth in Section 8(d) below.

" Indemnifying Party " has the meaning set forth in Section 8(d) below.

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" Intellectual Property " means (a) all inventions (whether patentable or unpatentable and whether or not reduced to practice), all improvements thereto, and all patents, patent applications, and patent disclosures, together with all reissues, continuations, continuations-in-part, revisions, extensions, and reexaminations thereof (collectively "Patents"), (b) all trademarks, service marks, trade dress, logos, trade names, corporate names and domain names, together with all translations, adaptations, derivations, and combinations thereof and including all goodwill associated therewith, and all applications, registrations, and renewals in connection therewith (collectively, "Marks"), (c) all copyrightable works, all copyrights, and all applications, registrations, and renewals in connection therewith (collectively "Copyrights"), (d) all mask works and all applications, registrations, and renewals in connection therewith, (e) 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) (collectively "Trade Secrets"), (f) all computer software (including data, compilations of data and related documentation) collectively, "Software"), (g) all other proprietary rights, and (h) all copies and tangible embodiments thereof (in whatever form or medium).

" Knowledge " means actual knowledge after reasonable investigation.

" Licenses In " has the meaning set forth in Section 4(1)(iii) below.

" Licenses Out " has the meaning set forth in Section 4(1)(iv) below.

" Licensed Intellectual Property " has the meaning set forth in Section 4(1)(iii) below.

" Most Recent Balance Sheet " means the balance sheet contained within the Most Recent Financial Statements.

" Most Recent Financial Statements " has the meaning set forth in Section 4(f) below.

" Most Recent Fiscal Month End " has the meaning set forth in Section 4(f) below.

" Most Recent Fiscal Year End " has the meaning set forth in Section 4(f) below.

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

" Owned Intellectual Property " has the meaning set forth in Section 4(1)(iii) below.

" Parent " has the meaning set forth in the preface above.

" Party " has the meaning set forth in the preface above.

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" Person " means an individual, a partnership, a corporation, an association, a joint stock company, a trust, a joint venture, an unincorporated organization, or a governmental entity (or any department, agency, or political subdivision thereof).

" Purchase Price " has the meaning set forth in Section 2(b) below.

" Purchase Shares " collectively means the shares of the Common Stock of the Buyer, without par value per share, paid to the Seller pursuant to Section 2(b)(i) below.

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

" Securities Act " means the Securities Act of 1933, as amended.

" Securities Exchange Act " means the Securities Exchange Act of 1934, as amended.

" Security Interest " means any mortgage, pledge, lien, encumbrance, charge, or other security interest, other than (a) mechanic’s, materialmen’s, and similar liens, (b) liens for taxes not yet due and payable, (c) purchase money liens and liens securing rental payments under capital lease arrangements, and (d) other liens arising in the Ordinary Course of Business and not incurred in connection with the borrowing of money.

" Seller " has the meaning set forth in the preface above.

" Target " has the meaning set forth in the preface above.

" Target Shares " collectively means (a) all issued and outstanding ordinary shares of the Target and (b) any ordinary shares held in treasury by the Target.

" Third Party Claim " has the meaning set forth in Section 8(d) below.

2 . Purchase and Sale of Target Shares .

(a) Basic Transaction . On and subject to the terms and conditions of this Agreement, the Buyer agrees to purchase from the Seller, and the Seller agrees to sell to the Buyer, all Target Shares for the consideration specified below in this Section 2.

(b) Purchase Price .

• (i) Purchase Price . The Parties have agreed that the purchase price for the Target Shares (the "Purchase Price") will be satisfied by the Buyer issuing 2,150,000 shares of its unregistered common stock, without par value per share, to the Seller (the "Purchase Shares"). The number of Purchase Shares to be so issued will not be adjusted to account for changes occurring between the date hereof and the Closing Date in the closing prices of the Seller’s common stock on the Nasdaq Capital Market or the Parent’s ordinary shares on the Australian Stock Exchange. The Buyer has engaged A&S to provide a fairness opinion regarding the Purchase Price.

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• (ii) Delivery of Purchase Price and Target Shares . On the Closing Date, the Buyer shall cause to be transferred to the Seller certificates for the Purchase Shares. The Purchase Shares shall be issued per instructions from the Seller. In exchange for the Purchase Shares, the Seller shall deliver to the Buyer the Target Shares, duly endorsed by the holder to the Buyer.

(c) The Closing . The closing of the transactions contemplated by this Agreement (the " Closing ") shall take place at the offices of the Buyer in Richmond, Virginia commencing at 9:00 a.m. local time on 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 actions the respective Parties will take at the Closing itself) or such other date as the Buyer and the Seller may mutually determine (the " Closing Date "); provided, however, that the Closing Date shall be no later than March 31, 2007.

(d) Deliveries at the Closing . At the Closing, (i) the Parent and the Seller will deliver to the Buyer the various certificates, instruments, and documents referred to in Section 7(a) below, (ii) the Buyer will deliver to the Parent and the Seller the various certificates, instruments, and documents referred to in Section 7(b) below, (iii) the Seller will deliver to the Buyer stock certificates representing the Target Shares it holds, endorsed in blank or accompanied by duly executed assignment documents, and (iv) the Buyer will deliver to the Seller the Purchase Shares.

3 . Representations and Warranties Concerning the Transaction .

(a) Representations and Warranties of the Parent and the Seller . The Parent and the Seller collectively represent and warrant to the Buyer that the statements contained in this Section 3(a) are correct and complete as of the date of this Agreement and will be correct and complete as of the Closing Date (as though made then and as though the Closing Date were substituted for the date of this Agreement throughout this Section 3(a)), except as set forth in Annex I attached hereto.

• (i) Organization of the Parent and the Seller . The Parent and the Seller are limited companies duly organized, validly existing, and in good standing under the laws of the Country of Australia, State of Victoria, including, but not limited to the Corporations Act.

  (ii) Authorization of Transaction . The Parent and the Seller have full power and authority to execute and deliver this Agreement and to perform its obligations hereunder. This Agreement constitutes the valid and legally binding obligation of the Parent and the Seller, enforceable in accordance with its terms and conditions. The Parent and the Seller need not give any notice to, make any filing with, or obtain any authorization, consent, or approval of any government or governmental agency in order to consummate the transactions contemplated by this Agreement. The Parent is not required by applicable law to obtain shareholder approval in order to consummate the transactions contemplated by this Agreement.

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• (iii) Noncontravention . Neither the execution and the delivery of this Agreement nor the consummation of the transactions contemplated hereby, will (A) violate any constitution, statute, regulation, rule, injunction, judgment, order, decree, ruling, charge, or other restriction of any government, governmental agency, or court to which the Parent or the Seller is subject or any provision of its constitution or other governing documents or (B) 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 Parent or the Seller is a party or by which either is bound or to which any of their assets is subject.

  (iv) Brokers’ Fees . Each of the Parent and the Seller have no liability or obligation to pay any fees or commissions to any broker, finder, or agent with respect to the transactions contemplated by this Agreement for which the Parent or the Buyer could become liable or obligated.

  (v) Target Shares . The Seller holds of record and owns beneficially all of the issued and outstanding Target Shares free and clear of any restrictions on transfer, taxes, Security Interests, options, warrants, purchase rights, contracts, commitments, equities, claims, and demands. The Seller is not a party to any option, warrant, purchase right, or other contract or commitment that could require the Seller to sell, transfer, or otherwise dispose of any capital stock of the Target (other than this Agreement). The Seller is not a party to any voting trust, proxy, or other agreement or understanding with respect to the voting of any capital stock of the Target.

  (vi) Investment . The Seller (A) understands that the Purchase Shares have not been, and will not be, registered under the Securities Act, or under any other securities laws, and are being offered and sold in reliance upon exemptions for transactions not involving any public offering, (B) is acquiring the Purchase Shares solely for its own account for investment purposes, and not with a view to the distribution, (C) is a sophisticated investor with knowledge and experience in business and financial matters, (D) 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 Purchase Shares, and (E) is able to bear the economic risk and lack of liquidity inherent in holding the Purchase Shares.

  (vii) Regulation S . The Seller is a "non-U.S. person" as defined in Regulation S of the Securities Act. The issuance of the Purchase Shares will be completed in an offshore transaction, as defined in Rule 902(h) of Regulation S of the Securities Act, as now in effect, and the Seller shall submit to the Buyer such further assurances of such status as may be reasonably requested by the Buyer. The Seller:

  (A) agrees to resell the Purchase Shares only in accordance with the provisions of Regulation S, pursuant to registration under the Securities Act or pursuant to an exemption from registration under the Securities Act;

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• (B) acknowledges that the Buyer is required to refuse to register any sale of the Purchase Shares unless the transfer is in accordance with the provisions of Regulation S, pursuant to registration under the Securities Act or pursuant to an exemption from registration under the Securities Act; and

  (C) agrees not to engage in hedging transactions with regards to the securities purchased unless in compliance with the Securities Act.

(b) Representations and Warranties of the Buyer . The Buyer represents and warrants to the Parent and the Seller that the statements contained in this Section 3(b) are correct and complete as of the date of this Agreement and will be correct and complete as of the Closing Date (as though made then and as though the Closing Date were substituted for the date of this Agreement throughout this Section 3(b)), except as set forth in Annex II attached hereto.

• (i) Organization of the Buyer . The Buyer is a corporation duly organized, validly existing, and in good standing under the laws of the Commonwealth of Virginia.

  (ii) Authorization of Transaction . The Buyer has full power and authority to execute and deliver this Agreement and to perform its obligations hereunder. This Agreement constitutes the valid and legally binding obligation of the Buyer, enforceable in accordance with its terms and conditions. With the exception of filing a proxy statement relating to the transaction contemplated by this Agreement with the SEC and responding to any comments thereto, the Buyer need not give any notice to, make any filing with, or obtain any authorization, consent, or approval of any government or governmental agency in order to consummate the transactions contemplated by this Agreement.

  (iii) Noncontravention . Neither the execution and the delivery of this Agreement, nor the consummation of the transactions contemplated hereby, will (A) violate any constitution, statute, regulation, rule, injunction, judgment, order, decree, ruling, charge, or other restriction of any government, governmental agency, or court to which the Buyer is subject or any provision of its articles of incorporation or bylaws or (B) 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 is a party or by which it is bound or to which any of its assets is subject.

  (iv) Brokers’ Fees . The Buyer has no liability or obligation to pay any fees or commissions to any broker, finder, or agent with respect to the transactions contemplated by this Agreement for which Seller or Parent could become liable or obligated.

  (v) Purchase Shares . The Buyer holds of record and owns beneficially the Purchase Shares which constitute the Purchase Price for the Target Shares, free and clear of any restrictions on transfer (other than any restrictions under the Securities Act and state securities laws), taxes, Security Interests, options, warrants, purchase rights, contracts, commitments, equities, claims, and demands.

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4 . Representations and Warranties Concerning the Target . The Parent and the Seller collectively represent and warrant to the Buyer that to the best of their collective knowledge and having made all reasonable investigations the statements contained in this Section 4 are correct and complete as of the date of this Agreement and will be correct and complete as of the Closing Date (as though made then and as though the Closing Date were substituted for the date of this Agreement throughout this Section 4), except as set forth in the disclosure schedule delivered by the Seller to the Buyer on the date hereof and initialed by the Parties (the "Disclosure Schedule" ). The Disclosure Schedule will be arranged in paragraphs corresponding to the lettered and numbered paragraphs contained in this Section 4.

(a) Organization, Qualification, and Corporate Power . The Target is a proprietary limited company duly organized, validly existing, and in good standing under the laws of the Country of Australia, State of Victoria, including, but not limited to, the Corporations Act. The Target is duly authorized to conduct business and is in good standing under the laws of each jurisdiction where such qualification is required, except where the lack of such qualification would not have a material adverse effect on the business, financial condition, operations, results of operations, or future prospects of the Target. The Target has full power and authority to carry on the businesses in which it is engaged and to own and use the properties owned and used by it. Section 4(a) of the Disclosure Schedule lists the directors and officers of the Target.

(b) Capitalization . The entire issued capital stock of the Target consists of 5,682,074 Target Shares. All of the Target Shares have been duly authorized, are validly issued, fully paid, and nonassessable, and are held of record by the Seller. There are no outstanding or authorized options, warrants, purchase rights, subscription rights, conversion rights, exchange rights, or other contracts or commitments that could require the Target to issue, sell, or otherwise cause to become outstanding any of its capital stock. There are no outstanding or authorized stock appreciation, phantom stock, profit participation, or similar rights with respect to the Target. There are no voting trusts, proxies, or other agreements or understandings with respect to the voting of the capital stock of the Target.

(c) Noncontravention . Neither the execution and the delivery of this Agreement, nor the consummation of the transactions contemplated hereby, will (i) violate any constitution, statute, regulation, rule, injunction, judgment, order, decree, ruling, charge, or other restriction of any government, governmental agency, or court to which the Target is subject or any provision of the charter or bylaws of the Target or (ii) 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 Target is a party or by which it is bound or to which any of its assets is subject (or result in the imposition of any Security Interest upon any of its assets). The Target does not need to give any notice to, make any filing with, or obtain any authorization, consent, or approval of any government or governmental agency in order for the Parties to consummate the transactions contemplated by this Agreement.

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(d) Brokers’ Fees . The Target has no liability or obligation to pay any fees or commissions to any broker, finder, or agent with respect to the transactions contemplated by this Agreement.

(e) Title to Assets . The Target has good and marketable title to, or a valid leasehold interest in, the properties and assets used by it, located on its premises, or shown on the Most Recent Balance Sheet or acquired after the date thereof, free and clear of all Security Interests, except for properties and assets disposed of in the Ordinary Course of Business since the date of the Most Recent Balance Sheet.

(f) Financial Statements . Attached hereto, as Section 4(f) of the Disclosure Schedule, are the following financial statements (collectively, the " Financial Statements "): (i) audited balance sheets and statements of income, dated as of June 30, 2006 (the " Most Recent Fiscal Year End ") for the Target; and (ii) unaudited and normalized balance sheets and statements of income, dated as of June 30, 2005. The Financial Statements (including the notes thereto) are correct and complete and consistent with the books and records of the Target, and present fairly the financial condition of the Target as of such dates and the results of operations of the Target for such periods; provided, however , that the Most Recent Financial Statements are subject to normal year-end adjustments (which will not be material individually or in the aggregate) and lack footnotes and other presentation items.

(g) Events Subsequent to Most Recent Fiscal Year End . Since the Most Recent Fiscal Year End, there has not been any material adverse change in the business, financial condition, operations, results of operations, or future prospects of the Target taken as a whole. Without limiting the generality of the foregoing, since that date:

• (i) the Target has not sold, leased, transferred, or assigned any assets, tangible or intangible, outside the Ordinary Course of Business;

  (ii) the Target has not entered into any agreement, contract, lease, or license outside the Ordinary Course of Business;

  (iii) no party (including the Target) has accelerated, terminated, made modifications to, or canceled any material agreement, contract, lease, or license to which the Target is a party or by which it is bound;

  (iv) the Target has not imposed any Security Interest upon any of its assets, tangible or intangible;

  (v) the Target has not made any capital expenditures outside the Ordinary Course of Business;

  (vi) the Target has not made any capital investment in, or any material loan to, any other Person outside the Ordinary Course of Business;

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• (vii) the Target has not created, incurred, assumed, or guaranteed any indebtedness for borrowed money and capitalized lease obligations;

  (viii) the Target has not granted any license or sublicense of any material rights under or with respect to any Intellectual Property;

  (ix) there has been no change made or authorized in the constitution of the Target;

  (x) the Target 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;

  (xi) the Target has not declared,