2-isopropylmalate synthase, bacterial-type (IPR005671)

Short name: LeuA_bact_synth

Overlapping homologous superfamilies

Family relationships



The branched-chain amino acids are synthesised by a common pathway that leads from pyruvate and alpha-ketobutyrate to valine and isoleucine, and a branch that leads from the immediate precursor of valine, alpha-ketoisovalerate, to leucine [PMID: 12626680]. This pathway operates in archaea, bacteria, fungi and plants, but not mammals, making the enzymes suitable targets for the development of novel antibiotics and herbicides.

Isopropylmalate synthase is the enzyme responsible for the the first committed step in the leucine branch of this biosynthetic pathway, the conversion of alpha-ketoisovalerate to alpha-isopropylmalate. It is either dimeric or tetrameric, depending on the organism, with a monomer molecular mass of 60-70 kDa, a dependence on divalent metal ions for activity, and an alkaline pH optimum [PMID: 4551511, PMID: 8117072, PMID: 8760908, PMID: 15159544]. Like many other biosynthetic enzymes it is subject to feedback inhibition by the end product of the pathway, leucine.

This entry represents the isopropylmalate synthase most commonly found in bacteria. A related form of this enzyme is found mainly in eukaryotes and some other bacteria (IPR005668). A homologous family in archaea may represent isozymes and/or related enzymes (IPR005675).

GO terms

Biological Process

GO:0009098 leucine biosynthetic process

Molecular Function

GO:0003852 2-isopropylmalate synthase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.