EC - 3-hydroxy-2-methylpyridine-5-carboxylate monooxygenase

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IntEnz Enzyme Nomenclature


Accepted name:
3-hydroxy-2-methylpyridine-5-carboxylate monooxygenase
Other names:
2-methyl-3-hydroxypyridine 5-carboxylic acid dioxygenase [incorrect]
3-hydroxy-3-methylpyridinecarboxylate dioxygenase [incorrect]
methylhydroxypyridine carboxylate dioxygenase [incorrect]
methylhydroxypyridinecarboxylate oxidase [misleading]
3-hydroxy-2-methylpyridine-5-carboxylate,NAD(P)H:oxygen oxidoreductase (decyclizing)
3-hydroxy-2-methylpyridinecarboxylate dioxygenase [incorrect]
Systematic name:
3-hydroxy-2-methylpyridine-5-carboxylate,NAD(P)H:oxygen oxidoreductase (ring-opening)




Contains FAD. The enzyme, characterized from the bacteria Pseudomonas sp. MA-1 and Mesorhizobium loti, participates in the degradation of pyridoxine (vitamin B6). Although the enzyme was initially thought to be a dioxygenase, oxygen-tracer experiments have shown that it is a monooxygnase, incorporating only one oxygen atom from molecular oxygen. The second oxygen atom that is incorporated into the product 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

Enzymes and pathways: NC-IUBMB , BRENDA , ERGO , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0047081
CAS Registry Number: 37256-69-2


  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 : 2590-2600 (1969). [PMID: 4306031]
  2. Chaiyen, P., Ballou, D. P., Massey, V.
    Gene cloning, sequence analysis, and expression of 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase.
    Proc. Natl. Acad. Sci. U.S.A. 94 : 7233-7238 (1997). [PMID: 9207074]
  3. Oonanant, W., Sucharitakul, J., Yuvaniyama, J., Chaiyen, P.
    Crystallization and preliminary X-ray crystallographic analysis of 2-methyl-3-hydroxypyridine-5-carboxylic acid (MHPC) oxygenase from Pseudomonas sp. MA-1.
    Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 61 : 312-314 (2005). [PMID: 16511028]
  4. Yuan, B., Yokochi, N., Yoshikane, Y., Ohnishi, K., Yagi, T.
    Molecular cloning, identification and characterization of 2-methyl-3-hydroxypyridine-5-carboxylic-acid-dioxygenase-coding gene from the nitrogen-fixing symbiotic bacterium Mesorhizobium loti.
    J. Biosci. Bioeng. 102 : 504-510 (2006). [PMID: 17270714]
  5. McCulloch, K. M., Mukherjee, T., Begley, T. P., Ealick, S. E.
    Structure of the PLP degradative enzyme 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase from Mesorhizobium loti MAFF303099 and its mechanistic implications.
    Biochemistry 48 : 4139-4149 (2009). [PMID: 19317437]
  6. Tian, B., Tu, Y., Strid, A., Eriksson, L. A.
    Hydroxylation and ring-opening mechanism of an unusual flavoprotein monooxygenase, 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase: a theoretical study.
    Chemistry 16 : 2557-2566 (2010). [PMID: 20066695]
  7. Tian, B., Strid, A., Eriksson, L. A.
    Catalytic roles of active-site residues in 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase: an ONIOM/DFT study.
    J Phys Chem B 115 : 1918-1926 (2011). [PMID: 21291225]

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