IUBMB Enzyme Nomenclature


Accepted name: 3-isopropylmalate dehydrogenase

Reaction: (2R,3S)-3-isopropylmalate + NAD+ = 4-methyl-2-oxopentanoate + CO2 + NADH + H+ (overall reaction)
(1a) (2R,3S)-3-isopropylmalate + NAD+ = (2S)-2-isopropyl-3-oxosuccinate + NADH + H+
(1b) (2S)-2-isopropyl-3-oxosuccinate = 4-methyl-2-oxopentanoate + CO2 (spontaneous)

For diagram of reaction click here.

Other name(s): β-isopropylmalic enzyme; β-isopropylmalate dehydrogenase; threo-Ds-3-isopropylmalate dehydrogenase; 3-carboxy-2-hydroxy-4-methylpentanoate:NAD+ oxidoreductase

Systematic name: (2R,3S)-3-isopropylmalate:NAD+ oxidoreductase

Comments: The product decarboxylates spontaneously to 4-methyl-2-oxopentanoate.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9030-97-1


1. Burns, R.O., Umbarger, H.E. and Gross, S.R. The biosynthesis of leucine. III. The conversion of α-hydroxy-β-carboxyisocaproate to α-ketoisocaproate. Biochemistry 2 (1963) 1053.

2. Parsons, S.J. and Burns, R.O. Purification and properties of β-isopropylmalate dehydrogenase. J. Biol. Chem. 244 (1969) 996-1003. [PMID: 4889950]

3. Németh, A., Svingor, Á., Pócsik, M., Dobó, J., Magyar, C, Szilåagyi, A., Gál, P. and Závodszky, P. Mirror image mutations reveal the significance of an intersubuit ion cluster in the stability of 3-isopropylmalate dehydrogenase. FEBS Lett. 468 (2000) 48-52. [PMID: 10683439]

4. Calvo, J. M., Stevens, C. M., Kalyanpur, M. G., and Umbarger, H. E. The absolute configuration of α-hydroxy-β-carboxyisocaproic acid (3-isopropylmalic acid), an intermediate in leucine biosynthesis. Biochemistry 3 (1964) 2024-2027. [PMID: 14269331]

[EC created 1972, modified 1976]

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