IUBMB Enzyme Nomenclature


Accepted name: dihydrolipoyllysine-residue (2-methylpropanoyl)transferase

Reaction: 2-methylpropanoyl-CoA + enzyme N6-(dihydrolipoyl)lysine = CoA + enzyme N6-(S-[2-methylpropanoyl]dihydrolipoyl)lysine

For diagram of reaction click here.

Glossary: dihydrolipoyl group

Other name(s): dihydrolipoyl transacylase

Systematic name: 2-methylpropanoyl-CoA:enzyme-N6-(dihydrolipoyl)lysine S-(2-methylpropanoyl)transferase

Comments: A multimer (24-mer) of this enzyme forms the core of the multienzyme 3-methyl-2-oxobutanoate dehydrogenase complex, and binds tightly both EC, 3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring) and EC, dihydrolipoyl dehydrogenase. The lipoyl group of this enzyme is reductively 2-methylpropanoylated by EC, and the only observed direction catalysed by EC is that where this 2-methylpropanoyl is passed to coenzyme A. In addition to the 2-methylpropanoyl group, formed when EC acts on the oxoacid that corresponds with valine, this enzyme also transfers the 3-methylbutanoyl and S-2-methylbutanoyl groups, donated to it when EC acts on the oxo acids corresponding with leucine and isoleucine.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 102784-26-9


1. Massey, L.K., Sokatch, J.R. and Conrad, R.S. Branched-chain amino acid catabolism in bacteria. Bacteriol. Rev. 40 (1976) 42-54. [PMID: 773366]

2. Chuang, D.T., Hu, C.C., Ku, L.S., Niu, W.L., Myers, D.E. and Cox R.P. Catalytic and structural properties of the dihydrolipoyl transacylase component of bovine branched-chain α-keto acid dehydrogenase. J. Biol. Chem. 259 (1984) 9277-9284. [PMID: 6746648]

3. Wynn, R.M., Davie, J.R., Zhi, W., Cox, R.P. and Chuang, D.T. In vitro reconstitution of the 24-meric E2 inner core of bovine mitochondrial branched-chain α-keto acid dehydrogenase complex: requirement for chaperonins GroEL and GroES. Biochemistry 33 (1994) 8962-8968. [PMID: 7913832]

4. Perham, R.N. Swinging arms and swinging domains in multifunctional enzymes: catalytic machines for multistep reactions. Annu. Rev. Biochem. 69 (2000) 961-1004. [PMID: 10966480]

[EC created 2003]

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