EXHIBIT 5.1


                OPINION OF PAUL, HASTINGS, JANOFSKY & WALKER LLP

June 6, 2005

Protein Polymer Technologies, Inc.
10655 Sorrento Valley Road
San Diego, California 92121

Ladies and Gentlemen:

         We are furnishing this opinion of counsel to Protein Polymer
Technologies, Inc., a Delaware corporation (the "Company"), for filing as
Exhibit 5.1 to the Registration Statement on Form S-2 (the "Registration
Statement") to be filed by the Company with the Securities and Exchange
Commission under the Securities Act of 1933, as amended, relating to the
issuance of 40,350,025 shares of the Company's common stock, $0.01 par value
(the "Shares").

         We have examined the Certificate of Incorporation and Bylaws, each as
amended to date, of the Company, and the originals, or copies certified or
otherwise identified, of records of corporate action of the Company as furnished
to us by the Company, certificates of public officials and of representatives of
the Company, and such other instruments and documents as we deemed necessary, as
a basis for the opinions hereinafter expressed. In such examination, we have
assumed the genuineness of all signatures, the authenticity of all corporate
records and other documents submitted to us and the conformity to original
documents submitted to us as certified or photostatic copies.

         Based upon our examination as aforesaid, and in reliance upon our
examination of such questions of law as we deem relevant under the
circumstances, we are of the opinion that the Shares, when purchased as
described in the Registration Statement, will be validly issued, fully paid and
nonassessable.

         We express no opinion with respect to the applicability or effect of
the laws of any jurisdiction other than the Delaware General Corporation Law, as
in effect as of the date hereof.

         We hereby consent to the filing of this opinion of counsel as Exhibit
5.1 to the Registration Statement.

                                       Very truly yours,

                                       /s/ Paul, Hastings, Janofsky & Walker LLP