| Primary Identifier | IPR004429 | Type | Family |
| Short Name | Isopropylmalate_DH |
| description | Several NAD- or NADP-dependent dehydrogenases, including 3-isopropylmalate dehydrogenase, tartrate dehydrogenase, and the dimeric forms of isocitrate dehydrogenase, share a nucleotide binding domain unrelated to that of lactate dehydrogenase and its homologues. These enzymes dehydrogenate their substates at a H-C-OH site adjacent to a H-C-COOH site; the latter carbon, now adjacent to a carbonyl group, readily decarboxylates. Among these decarboxylating dehydrogenases of hydroxyacids, overall sequence homology indicates evolutionary history rather than actual substrate or cofactor specifity, which may be toggled experimentally by replacement of just a few amino acids. 3-isopropylmalate dehydrogenase is an NAD-dependent enzyme and should have a sequence resembling HGSAPDI around residue 340. The subtrate binding loop should include a sequence resembling E[KQR]X(0,1)LLXXR around residue 115.3-isopropylmalate dehydrogenase (IPMDH or LeuB) is the third enzyme in leucine biosynthesis. It catalyzes the oxidation of 3-carboxy-2-hydroxy-4-methylpentanoate (3-isopropylmalate) to 3-carboxy-4-methyl-2-oxopentanoate []. In the yeast Glarea lozoyensis, 3-isopropylmalate dehydrogenase gloI (EC 1.1.1.85) is required for the biosynthesis of the mycotoxin pneumocandin, a lipohexapeptide of the echinocandin family []. |
