IUBMB Enzyme Nomenclature


Accepted name: quercetin 2,3-dioxygenase

Reaction: quercetin + O2 = 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate + CO + H+

For diagram of reaction click here

Other name(s): quercetinase; flavonol 2,4-oxygenase; quercetin:oxygen 2,3-oxidoreductase (decyclizing)

Systematic name: quercetin:oxygen 2,3-oxidoreductase (ring-opening)

Comments: The enzyme from Aspergillus sp. is a copper protein whereas that from Bacillus subtilis contains iron. Quercetin is a flavonol (5,7,3',4'-tetrahydroxyflavonol).

Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9075-67-6


1. Oka, T. and Simpson, F.J. Quercetinase, a dioxygenase containing copper. Biochem. Biophys. Res. Commun. 43 (1971) 1-5. [PMID: 5579942]

2. Steiner, R.A., Kalk, K.H. and Dijkstra, B.W. Anaerobic enzyme·substrate structures provide insight into the reaction mechanism of the copper-dependent quercetin 2,3-dioxygenase. Proc. Natl. Acad. Sci. USA 99 (2002) 16625-16630. [PMID: 12486225]

3. Bowater, L., Fairhurst, S.A., Just, V.J., and Bornemann, S. Bacillus subtilis YxaG is a novel Fe-containing quercetin 2,3-dioxygenase. FEBS Lett. 557 (2004) 45-48. [PMID: 14741339]

[EC created 1972]

Return to EC 1.13.11 home page
Return to EC 1.13 home page
Return to EC 1 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page