In enzymology, a 3-hydroxy-2-methylpyridinecarboxylate dioxygenase () is an enzyme that catalyzes the chemical reaction
The 5 substrates of this enzyme are 3-hydroxy-2-methylpyridine-5-carboxylate, NADH, NADPH, H<sup>+</sup>, and O<sub>2</sub>, whereas its 3 products are 2-(acetamidomethylene)succinate, NAD<sup>+</sup>, and NADP<sup>+</sup>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O<sub>2</sub> as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O<sub>2</sub> with NADH or NADPH as one donor, and incorporation of two atoms of oxygen into the other donor. The systematic name of this enzyme class is 3-hydroxy-2-methylpyridine-5-carboxylate,NAD(P)H:oxygen oxidoreductase (decyclizing). Other names in common use include methylhydroxypyridinecarboxylate oxidase, 2-methyl-3-hydroxypyridine 5-carboxylic acid dioxygenase, methylhydroxypyridine carboxylate dioxygenase, and 3-hydroxy-3-methylpyridinecarboxylate dioxygenase [incorrect]. This enzyme participates in vitamin B<sub>6</sub> metabolism. It employs one cofactor, FAD.