Entry |
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Name |
branched-chain alpha-keto acid dehydrogenase system;
branched-chain alpha-keto acid dehydrogenase complex;
2-oxoisovalerate dehydrogenase;
alpha-ketoisovalerate dehydrogenase;
2-oxoisovalerate dehydrogenase (acylating)
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Class |
Oxidoreductases;
Acting on the aldehyde or oxo group of donors;
With NAD+ or NADP+ as acceptor
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Sysname |
3-methyl-2-oxobutanoate:NAD+ 2-oxidoreductase (CoA-methylpropanoylating)
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Reaction(IUBMB) |
3-methyl-2-oxobutanoate + CoA + NAD+ = 2-methylpropanoyl-CoA + CO2 + NADH [RN: R01210]
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Reaction(KEGG) |
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Substrate |
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Product |
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Comment |
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-oxoacid dehydrogenase system family, which also includes EC 1.2.1.104, pyruvate dehydrogenase system, EC 1.2.1.105, 2-oxoglutarate dehydrogenase system, EC 1.4.1.27, glycine cleavage system, and EC 2.3.1.190, acetoin dehydrogenase system. With the exception of the glycine cleavage system, which contains 4 components, the 2-oxoacid dehydrogenase systems share a common structure, consisting of three main components, namely a 2-oxoacid 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.
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History |
EC 1.2.1.25 created 1972, modified 2019, modified 2020
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Reference |
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Authors |
Namba Y, Yoshizawa K, Ejima A, Hayashi T, Kaneda T. |
Title |
Coenzyme A- and nicotinamide adenine dinucleotide-dependent branched chain alpha-keto acid dehydrogenase. I. Purification and properties of the enzyme from Bacillus subtilis. |
Journal |
J Biol Chem 244:4437-47 (1969) |
Reference |
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Authors |
Pettit FH, Yeaman SJ, Reed LJ |
Title |
Purification and characterization of branched chain alpha-keto acid dehydrogenase complex of bovine kidney. |
Journal |
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Reference |
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Authors |
Harris RA, Hawes JW, Popov KM, Zhao Y, Shimomura Y, Sato J, Jaskiewicz J, Hurley TD |
Title |
Studies on the regulation of the mitochondrial alpha-ketoacid dehydrogenase complexes and their kinases. |
Journal |
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Reference |
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Authors |
AEvarsson A, Chuang JL, Wynn RM, Turley S, Chuang DT, Hol WG |
Title |
Crystal structure of human branched-chain alpha-ketoacid dehydrogenase and the molecular basis of multienzyme complex deficiency in maple syrup urine disease. |
Journal |
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Reference |
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Authors |
Reed LJ |
Title |
A trail of research from lipoic acid to alpha-keto acid dehydrogenase complexes. |
Journal |
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Other DBs |
ExplorEnz - The Enzyme Database: | 1.2.1.25 |
ExPASy - ENZYME nomenclature database: | 1.2.1.25 |
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LinkDB |
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