isobutyryl-coenzyme-a and 3-hydroxyisobutyric-acid

Dehydrogenation of (2S)-[3-13C]isobutyryl-CoA was carried out in vitro using 2-methyl-branched-chain acyl-CoA dehydrogenase purified from rat liver mitochondria. The product was subsequently hydrated by the addition of bovine crotonase. The resulting 3-hydroxyisobutyric acid was predominantly enriched with 13C at the beta-hydroxy position as determined as a methyl ester using electron ionization-gas chromatography-mass spectroscopy. This finding indicates that isobutyryl-CoA is dehydrogenated stereospecifically at the (pro-2S)-methyl and alpha-methine groups to form methacrylyl-CoA, which is later hydrated with the addition of hydrogen on the same side of the molecule from which it was subtracted to produce 3-hydroxyisobutyryl-CoA.

Topics: Acyl Coenzyme A; Animals; Gas Chromatography-Mass Spectrometry; Hydroxybutyrates; Methylation; Mitochondria, Liver; Molecular Conformation; Oxidoreductases; Oxidoreductases Acting on CH-CH Group Donors; Rats