| Comments |
This enzyme system catalyses the oxidative decarboxylation of branched-chain ¦Á-keto acids derived from L-leucine, L-isoleucine, and L-valine to branched-chain acyl-CoAs. It belongs to the 2-oxo acid dehydrogenase system family, which also includes the pyruvate dehydrogenase system, 2-oxoglutarate dehydrogenase system, and glycine cleavage system. With the exception of the glycine cleavage system, the 2-oxo acid dehydrogenase systems share a common structure, consisting of three main components, namely a 2-oxo acid dehydrogenase (E1), a dihydrolipoamide acyltransferase (E2), and dihydrolipoamide dehydrogenase (E3). The reaction catalysed by this system is the sum of three activities: EC 1.2.4.4, 3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring), EC 2.3.1.168, dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, and EC 1.8.1.4, dihydrolipoyl dehydrogenase. The system also acts on (S)-3-methyl-2-oxopentanoate and 4-methyl-2-oxopentanoate. |
