KEGG ENZYME: 1.2.1.25

ENZYME: 1.2.1.25

Entry

EC 1.2.1.25 Enzyme

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)

Class

Oxidoreductases;
Acting on the aldehyde or oxo group of donors;
With NAD+ or NADP+ as acceptor

Sysname

3-methyl-2-oxobutanoate:NAD+ 2-oxidoreductase (CoA-methyl-propanoylating)

Reaction(IUBMB)

3-methyl-2-oxobutanoate + CoA + NAD+ = 2-methylpropanoyl-CoA + CO2 + NADH [RN:R01210]

Reaction(KEGG)

R01210;
(other) R01651 R03171

Substrate

3-methyl-2-oxobutanoate [CPD:C00141];
CoA [CPD:C00010];
NAD+ [CPD:C00003]

Product

2-methylpropanoyl-CoA [CPD:C00630];
CO2 [CPD:C00011];
NADH [CPD:C00004]

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-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.

History

EC 1.2.1.25 created 1972, modified 2019

Reference

1 [PMID:4308861]

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

2 [PMID:283398]

Authors

Pettit FH, Yeaman SJ, Reed LJ.

Title

Purification and characterization of branched chain alpha-keto acid dehydrogenase complex of bovine kidney.

Journal

Proc Natl Acad Sci U S A 75:4881-5 (1978)
DOI:10.1073/pnas.75.10.4881

Reference

3 [PMID:9381974]

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

Adv Enzyme Regul 37:271-93 (1997)
DOI:10.1016/s0065-2571(96)00009-x

Reference

4 [PMID:10745006]

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

Structure 8:277-91 (2000)
DOI:10.1016/s0969-2126(00)00105-2

Reference

5 [PMID:11477096]

Authors

Reed LJ

Title

A trail of research from lipoic acid to alpha-keto acid dehydrogenase complexes.

Journal

J Biol Chem 276:38329-36 (2001)
DOI:10.1074/jbc.R100026200

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