The function of IVD (isovaleryl-CoA dehydrogenase, Ensembl gene identifier ENSG00000128928) is as follows. A mitochondrial matrix enzyme that catalyzes the third step in leucine catabolism, where isovaleryl-CoA (3-methylbutanoyl-CoA) is metabolized to 3-methylbut-2-enoyl-CoA (PubMed:7640268). To a lesser extent, it also participates in the first step in fatty acid beta- oxidation, in which it catalyzes the proR-proR stereospecific alpha,beta-dehydrogenation of other saturated short-chain acyl-CoA thioesters such as pentanoyl-CoA, hexanoyl-CoA and butanoyl-CoA, using the electron transfer flavoprotein (ETF) as their physiologic electron acceptor(PubMed:7640268). .