IUBMB Enzyme Nomenclature


Accepted name: acireductone dioxygenase (Ni2+-requiring)

Reaction: 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + O2 = 3-(methylsulfanyl)propanoate + formate + CO

For diagram click here or mechanism click here

Glossary: acireductone = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one

Other name(s): ARD; 2-hydroxy-3-keto-5-thiomethylpent-1-ene dioxygenase (ambiguous); acireductone dioxygenase (ambiguous); E-2; 1,2-dihydroxy-5-(methylthio)pent-1-en-3-one:oxygen oxidoreductase (formate- and CO-forming)

Systematic name: 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one:oxygen oxidoreductase (formate- and CO-forming)

Comments: Requires Ni2+. If iron(II) is bound instead of Ni2+, the reaction catalysed by EC, acireductone dioxygenase [iron(II)-requiring], occurs instead [1]. The enzyme from Klebsiella oxytoca (formerly Klebsiella pneumoniae) ATCC strain 8724 is involved in the methionine salvage pathway.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Wray, J.W. and Abeles, R.H. A bacterial enzyme that catalyzes formation of carbon monoxide. J. Biol. Chem. 268 (1993) 21466-21469. [PMID: 8407993]

2. Wray, J.W. and Abeles, R.H. The methionine salvage pathway in Klebsiella pneumoniae and rat liver. Identification and characterization of two novel dioxygenases. J. Biol. Chem. 270 (1995) 3147-3153. [PMID: 7852397]

3. Furfine, E.S. and Abeles, R.H. Intermediates in the conversion of 5'-S-methylthioadenosine to methionine in Klebsiella pneumoniae. J. Biol. Chem. 263 (1988) 9598-9606. [PMID: 2838472]

4. Dai, Y., Wensink, P.C. and Abeles, R.H. One protein, two enzymes. J. Biol. Chem. 274 (1999) 1193-1195. [PMID: 9880484]

5. Mo, H., Dai, Y., Pochapsky, S.S. and Pochapsky, T.C. 1H, 13C and 15N NMR assignments for a carbon monoxide generating metalloenzyme from Klebsiella pneumoniae. J. Biomol. NMR 14 (1999) 287-288. [PMID: 10481280]

6. Dai, Y., Pochapsky, T.C. and Abeles, R.H. Mechanistic studies of two dioxygenases in the methionine salvage pathway of Klebsiella pneumoniae. Biochemistry 40 (2001) 6379-6387. [PMID: 11371200]

7. Al-Mjeni, F., Ju, T., Pochapsky, T.C. and Maroney, M.J. XAS investigation of the structure and function of Ni in acireductone dioxygenase. Biochemistry 41 (2002) 6761-6769. [PMID: 12022880]

8. Pochapsky, T.C., Pochapsky, S.S., Ju, T., Mo, H., Al-Mjeni, F. and Maroney, M.J. Modeling and experiment yields the structure of acireductone dioxygenase from Klebsiella pneumoniae. Nat. Struct. Biol. 9 (2002) 966-972. [PMID: 12402029]

[EC created 2006]

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