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                     U.S. SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 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*

   Grau                 Ulrich                  M.
- --------------------------------------------------------------------------------
   (Last)               (First)                 (Middle)

   c/o Enzon, Inc., 685 Route 202/206
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                                    (Street)

   Bridgewater         New Jersey               08807
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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 Identification Number of Reporting Person, if an Entity (Voluntary)


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4. Statement for Month/Year

   June 30, 2002
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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)

   ________________________________________________
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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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* If the Form is filed by more than one Reporting Person, see Instruction
  4(b)(v).


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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) and 4) (Instr.4) (Instr. 4) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ ====================================================================================================================================
* If the form is filed by more than one reporting person, see Instruction 4(b)(v). 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) - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock (a) Common (right to buy) $45.98 3/15/02 A 100,000 (b) 3/15/12 Stock 100,000 -- 100,000 D - ------------------------------------------------------------------------------------------------------------------------------------ Common Stock (a) Common (right to buy) $45.98 3/15/02 A 50,000 (c) 3/15/12 Stock 50,000 -- 50,000 D - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ ====================================================================================================================================
Explanation of Responses: (a) Acquired pursuant to the Company's Non-Qualified Stock Option Plan and qualified under Rule 16b-3. (b) The Options shall become exercisable as to 20,000 shares on each of the first, second, third, fourth and fifth anniversaries of March 15, 2002. The Options are subject to accelerated vesting upon the occurrence of certain events as provided in the Employment Agreement, dated as of March 6, 2002, between the Company and Reporting Person (the "Employment Agreement"). (c) The Options shall become exercisable on March 15, 2007. The Options are subject to accelerated vesting upon the occurrence of certain events as provided in the Employment Agreement. - --------------------------------------------- ----------------------- **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. Potential persons who are to respond to the collections of information contained in this form are not required to respond unless the form displays a currently valid OMB number. Page 2