U.S. SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                     FORM 5

               ANNUAL STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

    Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934,
       Section 17(a) of the Public Utility Holding Company Act of 1935 or
               Section 30(f) of the Investment Company Act of 1940

[  ] Check this box if no longer subject of Section 16. Form 4 or Form 5
     obligations may continue. See Instruction 1(b).

[  ] Form 3 Holdings Reported

[  ] Form 4 Transactions Reported

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1. Name and Address of Reporting Person

Zuerblis                Kenneth                    G.
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   (Last)               (First)                 (Middle)

c/o Enzon, Inc.          20 Kingbridge Road  
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                                    (Street)
          
Piscataway,                NJ                     08854
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   (City)               (State)                 (Zip)


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2. Issuer Name and Ticker or Trading Symbol


Enzon, Inc. (ENZN)
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3. IRS or Social Security Number of Reporting Person (Voluntary)


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4. Statement for Month/Year

June 30, 1997
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5. If Amendment, Date of Original (Month/Year)


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6. Relationship of Reporting Person to Issuer
   (Check all applicable)

   [   ]   Director                             [   ]   10% Owner
   [ x ]   Officer (give title below)           [   ]   Other (specify below)


          Vice President, Finance
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7.  Individual or Joint/Group Filing
    (Check applicable line)

  [ x ] Form filed by One Reporting Person
  [   ] Form filed by More than One Reporting Person



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           Table I -- Non-Derivative Securities Acquired, Disposed of,
                             or Beneficially Owned
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5. 6. 4. Amount of Owner- Security Acquired (A) or Securities ship Disposed of (D) Beneficially Form: 7. (Instr. 3, 4 and 5) Owned at End Direct Nature of 2. 3. ----------------------------- of Issuer's (D) or Indirect 1. Transaction Transaction (A) Fiscal Year Indirect Beneficial Title of Security Date Code Amount or Price (Instr. 3 (I) Ownership (Instr. 3) (mm/dd/yy) (Instr. 8) (D) & 4) (Instr.4) (Instr. 4) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ ====================================================================================================================================
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly FORM 5 (continued) Table II -- Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities) ================================================================================
9. 10. Number Owner- of ship 2. Deriv- of Conver- 5. 7. ative Deriv- 11. sion Number of Title and Amount Secur- ative Nature or Derivative 6. of Underlying 8. ities Secur- of Exer- Securities Date Securities Price Bene- ity: In- cise 3. Acquired (A) Exercisable and (Instr. 3 and 4) of ficially Direct direct Price Trans- 4. or Disposed Expiration Date ---------------- Deriv- Owned (D) or Bene- 1. of action Trans- of (D) (Month/Day/Year) Amount ative at End In- ficial Title of Deriv- Date action (Instr. 3, ---------------- or Secur- of direct Owner- Derivative ative (Month/ Code 4 and 5) Date Expira- Number ity Year (I) ship Security Secur- Day/ (Instr. ------------ Exer- tion of (Instr. (Instr. (Instr. (Instr. (Instr. 3) ity Year) 8) (A) (D) cisable Date Title Shares 5) 4) 4) 4) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ Stock Option (1) Common (right to buy) $2.8125 07/23/96 A 50,000 (2) 7/23/06 Stock 50,000 50,000 D - ------------------------------------------------------------------------------------------------------------------------------------ Stock Option (1) Common (right to buy) $2.5625 02/11/97 A 40,000 (3) 2/11/07 Stock 40,000 40,000 D - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ ====================================================================================================================================
Explanation of Responses: (1) Granted under the Company's Non-qualified Stock Option Plan and qualified under Rule 16b-3. (2) Option vests and becomes exercisable in two installments of 25,000 shares each on July 23, 1997 and July 23, 1998, respectively. (3) Option vests and becomes exercisable in two installments of 20,000 shares each on February 11, 1998 and February 11, 1999, respectively. /S/KENNETH J. ZUERBLIS 07/22/97 - --------------------------------------------- ----------------------- **Signature of Reporting Person Date ** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space provided is insufficient, see Instruction 6 for procedure.