Quercetin 2,3-dioxygenase

In enzymology, a quercetin 2,3-dioxygenase (EC 1.13.11.24) is an enzyme that catalyzes the chemical reaction

quercetin + O₂ ${\displaystyle \rightleftharpoons }$ 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate + CO + H⁺

quercetin 2,3-dioxygenase
Crystal structure of quercetin 2,3-dioxygenase from pdb entry 1H1I with quercetin and copper.
Identifiers
EC no.	1.13.11.24
CAS no.	9075-67-6
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

Thus, the two substrates of this enzyme are quercetin and O₂, whereas its three products are 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate, CO, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O₂ as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O₂. The systematic name of this enzyme class is quercetin:oxygen 2,3-oxidoreductase (decyclizing). Other names in common use include quercetinase and flavonol 2,4-oxygenase. It has two cofactors: iron and copper.

Structural studies

As of late 2007, six crystal structures have been solved for this class of enzymes, with PDB accession codes 1GQG, 1GQH, 1H1I, 1H1M, 1JUH, and 2H0V.