3-hydroxyisobutyrate dehydrogenase
(3-hydroxy-2-methylpropanoate:NAD(+) oxidoreductase, EC 1.1.1.31)
is a dimeric mitochondrial enzyme that catalyzes the
NAD(+)-dependent, reversible oxidation of 3-hydroxyisobutyrate, an
intermediate of valine catabolism, to methylmalonate
semialdehyde.
