methylmalonyl semialdehyde + NADH + H+ <=> beta-hydroxyisobutyrate + NAD+ Authored: D'Eustachio, P, 2010-02-18 EC Number: 1.1.1.31 Edited: D'Eustachio, P, 2010-02-18 Mitochondrial 3-hydroxyisobutyrate dehydrogenase (HIBADH) catalyzes the reversible reaction of methylmalonyl semialdehyde and NADH + H+ to form beta-hydroxyisobutyrate and NAD+. The biochemical properties of human HIBADH are inferred from those of its better-studied porcine homologue (Robinson and Coon 1957). Unpublished crystallographic studies (PDB 2GF2) have shown the active enzyme to be a tetramer of HIBADH polypeptides whose aminoterminal 40 residues, a mitochondrial targeting sequence, have been removed. Pubmed13416257 Reactome Database ID Release 43508473 Reactome, http://www.reactome.org ReactomeREACT_21400 Reviewed: Jassal, B, 2010-02-26