EC - Quercetin 2,3-dioxygenase

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IntEnz Enzyme Nomenclature


Accepted name:
quercetin 2,3-dioxygenase
Other names:
flavonol 2,4-oxygenase
quercetin:oxygen 2,3-oxidoreductase (decyclizing)
Systematic name:
quercetin:oxygen 2,3-oxidoreductase (ring-opening)




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

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UM-BBD , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0008127
CAS Registry Number: 9075-67-6
UniProtKB/Swiss-Prot: (19) [show] [UniProt]


  1. Oka, T. and Simpson, F.J.
    Quercetinase, a dioxygenase containing copper.
    Biochem. Biophys. Res. Commun. 43: 1-5 (1971). [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: 16625-16630 (2002). [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: 45-48 (2004). [PMID: 14741339]

[EC created 1972]