3-Hydroxyisobutyrate Dehydrogenase (HIBADH)

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.Rougraff et al. (1989) cloned rat liver Hibadh. The deduced 300-amino acid protein contains an N-terminal nucleotide-binding domain. The amino acid sequence shows similarity to several other mammalian pyridine nucleotide-dependent dehydrogenases. Northern blot analysis detected expression of an approximately 2.0-kb transcript in all rat tissues examined, which included kidney, liver, heart, and muscle.