3-methyl-2-oxobutanoate dehydrogenase

3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring)

Identifiers

EC number

1.2.4.4

Databases

PDB structures

AmiGO / EGO

Search
PMC	articles
PubMed	articles
NCBI	proteins

In enzymology, a 3-methyl-2-oxobutanoate dehydrogenase (EC 1.2.4.4) is an enzyme that catalyzes the chemical reaction

3-methyl-2-oxobutanoate + [dihydrolipoyllysine-residue (2-methylpropanoyl)transferase] lipoyllysine

\rightleftharpoons

[dihydrolipoyllysine-residue (2-methylpropanoyl)transferase] S-(2-methylpropanoyl)dihydrolipoyllysine + CO₂

The 3 substrates of this enzyme are 3-methyl-2-oxobutanoate, dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, and lipoyllysine, whereas its 3 products are dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, S-(2-methylpropanoyl)dihydrolipoyllysine, and CO₂.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with a disulfide as acceptor.

This enzyme participates in valine, leucine and isoleucine degradation. It employs one cofactor, thiamin diphosphate.

Structural studies

As of late 2007, 29 structures have been solved for this class of enzymes, with PDB accession codes 1DTW, 1OLS, 1OLU, 1OLX, 1U5B, 1UM9, 1UMB, 1UMC, 1UMD, 1V11, 1V16, 1V1M, 1V1R, 1WCI, 1X7W, 1X7X, 1X7Y, 1X7Z, 1X80, 2BEU, 2BEV, 2BEW, 2BFB, 2BFC, 2BFD, 2BFE, 2BFF, 2BP7, and 2J9F.

References

Bowden JA, Connelly JL (1968). "Branched chain alpha-keto acid metabolism. II. Evidence for the common identity of alpha-ketoisocaproic acid and alpha-keto-beta-methyl-valeric acid dehydrogenases". J. Biol. Chem. 243 (12): 3526–31. PMID 5656388.
Connelly JL, Danner DJ, Bowden JA (1968). "Branched chain alpha-keto acid metabolism. I. Isolation, purification, and partial characterization of bovine liver alpha-ketoisocaproic:alpha-keto-beta-methylvaleric acid dehydrogenase". J. Biol. Chem. 243 (6): 1198–203. PMID 5689906.
Danner DJ, Lemmon SK, Besharse JC, Elsas LJ 2nd (1979). "Purification and characterization of branched chain alpha-ketoacid dehydrogenase from bovine liver mitochondria". J. Biol. Chem. 254 (12): 5522–6. PMID 447664.
Pettit FH, Yeaman SJ, Reed LJ (1978). "Purification and characterization of branched chain alpha-keto acid dehydrogenase complex of bovine kidney". Proc. Natl. Acad. Sci. U.S.A. 75 (10): 4881–5. doi:10.1073/pnas.75.10.4881. PMC 336225. PMID 283398.
Perham RN (2000). "Swinging arms and swinging domains in multifunctional enzymes: catalytic machines for multistep reactions". Annu. Rev. Biochem. 69 (1): 961–1004. doi:10.1146/annurev.biochem.69.1.961. PMID 10966480.

Aldehyde/oxo oxidoreductases (EC 1.2)

1.2.1: NAD or NADP	Aldehyde dehydrogenase Acetaldehyde dehydrogenase Long-chain-aldehyde dehydrogenase

1.2.2: cytochrome	Formate dehydrogenase (cytochrome)

1.2.3: oxygen	Aldehyde oxidase

1.2.4: disulfide	Oxoglutarate dehydrogenase complex Pyruvate dehydrogenase Branched-chain alpha-keto acid dehydrogenase complex BCKDHA BCKDHB DBT DLD

1.2.7: iron-sulfur protein	Pyruvate synthase

Proteins: enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases(list) EC2 Transferases(list) EC3 Hydrolases(list) EC4 Lyases(list) EC5 Isomerases(list) EC6 Ligases(list)

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