EC 22.214.171.124 Enzyme
branched-chain alpha-keto acid dehydrogenase system;
branched-chain alpha-keto acid dehydrogenase complex;
2-oxoisovalerate dehydrogenase (acylating)
Acting on the aldehyde or oxo group of donors;
With NAD+ or NADP+ as acceptor
3-methyl-2-oxobutanoate:NAD+ 2-oxidoreductase (CoA-methyl-propanoylating)
3-methyl-2-oxobutanoate + CoA + NAD+ = 2-methylpropanoyl-CoA + CO2 + NADH [RN:
This enzyme system catalyses the oxidative decarboxylation of branched-chain alpha-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
, 3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring), EC
, dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, and EC
, dihydrolipoyl dehydrogenase. The system also acts on (S)-3-methyl-2-oxopentanoate and 4-methyl-2-oxopentanoate.
EC 126.96.36.199 created 1972, modified 2019
Namba Y, Yoshizawa K, Ejima A, Hayashi T, Kaneda T.
Coenzyme A- and nicotinamide adenine dinucleotide-dependent branched chain alpha-keto acid dehydrogenase. I. Purification and properties of the enzyme from Bacillus subtilis.
J Biol Chem 244:4437-47 (1969)
Pettit FH, Yeaman SJ, Reed LJ.
Purification and characterization of branched chain alpha-keto acid dehydrogenase complex of bovine kidney.
Proc Natl Acad Sci U S A 75:4881-5 (1978)
Harris RA, Hawes JW, Popov KM, Zhao Y, Shimomura Y, Sato J, Jaskiewicz J, Hurley TD
Studies on the regulation of the mitochondrial alpha-ketoacid dehydrogenase complexes and their kinases.
Adv Enzyme Regul 37:271-93 (1997)
AEvarsson A, Chuang JL, Wynn RM, Turley S, Chuang DT, Hol WG
Crystal structure of human branched-chain alpha-ketoacid dehydrogenase and the molecular basis of multienzyme complex deficiency in maple syrup urine disease.
Structure 8:277-91 (2000)
A trail of research from lipoic acid to alpha-keto acid dehydrogenase complexes.
J Biol Chem 276:38329-36 (2001)
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