methylmalonate semialdehyde + NAD+ + CoA => propionyl-CoA + CO2 + NADH + H+ EC Number: 1.2.1.27 Mitochondrial methylmalonate semialdehyde dehydrogenase (ALDH6A1) catalyzes the reaction of methylmalonate semialdehyde, NAD+, and CoA to form propionyl-CoA, CO2, and NADH + H+. A human ALDH6A1 gene has been cloned. Its sequence is closely homologous to that of the better-characterized rat enzyme (Kedishvili et al. 1992) and a missense mutation in a normally well-conserved codon has been found in the allele of the gene from a patient with a defect in methylmalonic semialdehyde dehydrogenase activity (Chambliss et al. 2000). Pubmed10947204 Pubmed1527093 Reactome Database ID Release 4370893 Reactome, http://www.reactome.org ReactomeREACT_1077