IUBMB Enzyme Nomenclature


Accepted name: 5-pyridoxate monooxygenase

Reaction: 3-hydroxy-4-hydroxymethyl-2-methylpyridine-5-carboxylate + NADPH + H+ + O2 = 2-(acetamidomethylene)-3-(hydroxymethyl)succinate + NADP+

Glossary: 3-hydroxy-4-hydroxymethyl-2-methylpyridine-5-carboxylate = 5-pyridoxate

Other name(s): 5-pyridoxate,NADPH:oxygen oxidoreductase (decyclizing); 5-pyridoxate oxidase (misleading); 5-pyridoxate dioxygenase (incorrect)

Systematic name: 5-pyridoxate,NADPH:oxygen oxidoreductase (ring-opening)

Comments: Contains FAD. The enzyme, characterized from the bacterium Arthrobacter sp. Cr-7, participates in the degradation of pyridoxine (vitamin B6). Although the enzyme was initially thought to be a dioxygenase, oxygen-tracer experiments have suggested that it is a monooxygenase, incorporating only one oxygen atom from molecular oxygen into the product. The second oxygen atom originates from a water molecule, which is regenerated during the reaction and thus does not show up in the reaction equation.

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


1. Sparrow, L.G., Ho, P.P.K., Sundaram, T.K., Zach, D., Nyns, E.J. and Snell, E.E. The bacterial oxidation of vitamin B6. VII. Purification, properties, and mechanism of action of an oxygenase which cleaves the 3-hydroxypyridine ring. J. Biol. Chem. 244 (1969) 2590-2600. [PMID: 4306031]

2. Nelson, M.J. and Snell, E.E. Enzymes of vitamin B6 degradation. Purification and properties of 5-pyridoxic-acid oxygenase from Arthrobacter sp. J. Biol. Chem 261 (1986) 15115-15120. [PMID: 3771566]

3. Chaiyen, P. Flavoenzymes catalyzing oxidative aromatic ring-cleavage reactions. Arch. Biochem. Biophys. 493 (2010) 62-70. [PMID: 19728986]

[EC created 2018 (EC created 1972, incorporated 2018)]

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