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 220.127.116.11, 3-methyl-2-oxobutanoate dehydrogenase (2-methylpropanoyl-transferring) and EC 18.104.22.168, dihydrolipoyl dehydrogenase. The lipoyl group of this enzyme is reductively 2-methylpropanoylated by EC 22.214.171.124, and the only observed direction catalysed by EC 126.96.36.199 is that where this 2-methylpropanoyl is passed to coenzyme A. In addition to the 2-methylpropanoyl group, formed when EC 188.8.131.52 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 184.108.40.206 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
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