EC 1.2.4.4 - 3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring)

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IntEnz Enzyme Nomenclature
EC 1.2.4.4

Names

Accepted name:
3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring)
Other names:
2-oxoisocaproate dehydrogenase
2-oxoisovalerate (lipoate) dehydrogenase
3-methyl-2-oxobutanoate dehydrogenase (lipoamide)
3-methyl-2-oxobutanoate:lipoamide oxidoreductase (decarboxylating and acceptor-2-methylpropanoylating)
α-keto-α-methylvalerate dehydrogenase
α-ketoisocaproate dehydrogenase
α-ketoisocaproic dehydrogenase
α-ketoisocaproic-α-keto-α-methylvaleric dehydrogenase
α-ketoisovalerate dehydrogenase
α-oxoisocaproate dehydrogenase
BCKDH
BCOAD
branched chain keto acid dehydrogenase
branched-chain (-2-oxoacid) dehydrogenase (BCD)
branched-chain 2-keto acid dehydrogenase
branched-chain 2-oxo acid dehydrogenase
branched-chain α-keto acid dehydrogenase
branched-chain α-oxo acid dehydrogenase
branched-chain keto acid dehydrogenase
branched-chain ketoacid dehydrogenase
dehydrogenase, 2-oxoisovalerate (lipoate)
dehydrogenase, branched chain α-keto acid
Systematic name:
3-methyl-2-oxobutanoate:[dihydrolipoyllysine-residue (2-methylpropanoyl)transferase]-lipoyllysine 2-oxidoreductase (decarboxylating, acceptor-2-methylpropanoylating)

Reaction

Cofactor

Comments:

Contains thiamine diphosphate. It acts not only on 3-methyl-2-oxobutanaoate, but also on 4-methyl-2-oxopentanoate and (S)-3-methyl-2-oxopentanoate, so that it acts on the 2-oxo acids that derive from the action of transaminases on valine, leucine and isoleucine. It is a component of the multienzyme 3-methyl-2-oxobutanoate dehydrogenase complex in which multiple copies of it are bound to a core of molecules of EC 2.3.1.168, dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, which also binds multiple copies of EC 1.8.1.4, dihydrolipoyl dehydrogenase. It does not act on free lipoamide or lipoyllysine, but only on the lipoyllysine residue in EC 2.3.1.168.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003863
CAS Registry Number: 9082-72-8
UniProtKB/Swiss-Prot: (31) [show] [UniProt]

References

  1. Bowden, J.A. and Connelly, J.L.
    Branched chain α-keto acid metabolism. II. Evidence for the common identity of α-ketoisocaproic acid and α-keto-β-methyl-valeric acid dehydrogenases.
    J. Biol. Chem. 243: 3526-3531 (1968). [PMID: 5656388]
  2. Connelly, J.L., Danner, D.J. and Bowden, J.A.
    Branched chain α-keto acid metabolism. I. Isolation, purification, and partial characterization of bovine liver α-ketoisocaproic:α-keto-β-methylvaleric acid dehydrogenase.
    J. Biol. Chem. 243: 1198-1203 (1968). [PMID: 5689906]
  3. Danner, D.J., Lemmon, S.K., Beharse, J.C.
    and Elsas, L.J., II, Purification and characterization of branched chain α-ketoacid dehydrogenase from bovine liver mitochondria.
    J. Biol. Chem. 254: 5522-5526 (1979). [PMID: 447664]
  4. Pettit, F.H., Yeaman, S.J. and Reed, L.J.
    Purification and characterization of branched chain α-keto acid dehydrogenase complex of bovine kidney.
    Proc. Natl. Acad. Sci. USA 75: 4881-4885 (1978). [PMID: 283398]
  5. Perham, R.N.
    Swinging arms and swinging domains in multifunctional enzymes: catalytic machines for multistep reactions.
    Annu. Rev. Biochem. 69: 961-1004 (2000). [PMID: 10966480]

[EC 1.2.4.4 created 1972 (EC 1.2.4.3 created 1972, incorporated 1978), modified 2003]