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

Classon,                 Rolf                     A.
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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)

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



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7.   Individual or Joint/Group Filing
     (check applicabel 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) - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock(1) 03/31/97 P 1,561 A $2.5625 D - ---------------------------------------------------------------------------------------------------------------------------- Common Stock(1) 06/30/97 P 1,556 A $2.25 3,117 D - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ ====================================================================================================================================
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) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ ====================================================================================================================================
Explanation of Responses: (1) Purchased pursuant to the Company's 1996 Independent Directors Stock Plan and qualified under Rule 16b-3. /S/ROLF A. CLASSON 07/21/97 - --------------------------------------------- ----------------------- **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.