EXHIBIT 4.3


                            CERTIFICATE OF AMENDMENT
                                     OF THE
                          CERTIFICATE OF INCORPORATION
                              OF ENZO BIOCHEM, INC.


                        UNDER SECTION 805 OF THE BUSINESS
                                 CORPORATION LAW

         WE,  the  undersigned,  ELAZAR  RABBANI  and  BARRY  W.  WEINER,  being
respectively  the  President  and  Secretary of ENZO  BIOCHEM,  INC.,  do hereby
certify:

         1.       The name of the Corporation is ENZO BIOCHEM, INC.

         2.       The Certificate of  Incorporation  was filed by the Department
of  State  on  August  13,  1976.

         3.       The Certificate of  Incorporation  is hereby amended to affect
the following changes authorized by the Business Corporation Law:

                  (A)      To increase the capitalization of the Corporation.

                  (B)      To change the address to which the Secretary of State
                           shall mail a copy of process  against the Corporation
                           served upon him.

         4.       To accomplish the  foregoing:

                  (A)      Article 4 is hereby amended to read as follows:

                           "4.  The   aggregate   number  of  shares  which  the
                           Corporation  shall  have  authority  to issue is five
                           million  (30,000,000)  shares,  one  ($.01)  cent par
                           value,  per share,  all of which shall be  designated
                           Common Stock."

                  (B)      Article 5 is hereby amended to read as follows:

                           "5. The  Secretary of State of New York is designated
                           as the agent of the  Corporation  upon  whom  process
                           against  it may be  served.  The  Secretary  of State
                           shall  mail  a  copy  of  any  process   against  the
                           Corporation  which  may  be  served  upon  him to the
                           Corporation  c/o Elazar  Rabbani,  325 Hudson Street,
                           New York, New York 10013."


         5.       The foregoing  amendments  were  authorized by the vote of the
holders of a majority of all  outstanding  shares  entitled to vote thereon at a
meeting of shareholders held on the 29h day of March 1981.

         IN WITNESS  THEREOF,  we have signed this Certificate on the 3rd day of
June 1981 and we affirm the statements contained herein as true under penalty of
perjury.


                                              /s/
                                              ----------------------------------
                                              Elazar Rabbani, President



                                              /s/
                                              ----------------------------------
                                              Barry W. Weiner, Secretary

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