IUBMB Enzyme Nomenclature


Accepted name: meromycolic acid enoyl-[acyl-carrier-protein] reductase

Reaction: a meromycolyl-[acyl-carrier protein] + NAD+ = a trans2-meromycolyl-[acyl-carrier protein] + NADH + H+

Glossary: meromycolic acids are one of the two precursors of the mycolic acids produced by Mycobacteria. They consist of a long chain typically of 50-60 carbons, which is functionalized by different groups.

Other name(s): inhA (gene name)

Systematic name: meromycolyl-[acyl-carrier protein]:NAD+ oxidoreductase

Comments: InhA is a component of the fatty acid synthase (FAS) II system of Mycobacterium tuberculosis, catalysing an enoyl-[acyl-carrier-protein] reductase step. The enzyme acts on very long and unsaturated fatty acids that form the meromycolic component of mycolic acids. It extends FASI-derived C20 fatty acids to form C60 to C90 mycolic acids. The enzyme, which forms a homotetramer, is the target of the preferred antitubercular drug isoniazid.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Quemard, A., Sacchettini, J.C., Dessen, A., Vilcheze, C., Bittman, R., Jacobs, W.R., Jr. and Blanchard, J.S. Enzymatic characterization of the target for isoniazid in Mycobacterium tuberculosis. Biochemistry 34 (1995) 8235-8241. [PMID: 7599116]

2. Rozwarski, D.A., Vilcheze, C., Sugantino, M., Bittman, R. and Sacchettini, J.C. Crystal structure of the Mycobacterium tuberculosis enoyl-ACP reductase, InhA, in complex with NAD+ and a C16 fatty acyl substrate. J. Biol. Chem. 274 (1999) 15582-15589. [PMID: 10336454]

3. Marrakchi, H., Laneelle, G. and Quemard, A. InhA, a target of the antituberculous drug isoniazid, is involved in a mycobacterial fatty acid elongation system, FAS-II. Microbiology 146 (2000) 289-296. [PMID: 10708367]

4. Vilcheze, C., Morbidoni, H.R., Weisbrod, T.R., Iwamoto, H., Kuo, M., Sacchettini, J.C. and Jacobs, W.R., Jr. Inactivation of the inhA-encoded fatty acid synthase II (FASII) enoyl-acyl carrier protein reductase induces accumulation of the FASI end products and cell lysis of Mycobacterium smegmatis. J. Bacteriol. 182 (2000) 4059-4067. [PMID: 10869086]

5. Gurvitz, A., Hiltunen, J.K. and Kastaniotis, A.J. Function of heterologous Mycobacterium tuberculosis InhA, a type 2 fatty acid synthase enzyme involved in extending C20 fatty acids to C60-to-C90 mycolic acids, during de novo lipoic acid synthesis in Saccharomyces cerevisiae. Appl. Environ. Microbiol. 74 (2008) 5078-5085. [PMID: 18552191]

6. Chollet, A., Mourey, L., Lherbet, C., Delbot, A., Julien, S., Baltas, M., Bernadou, J., Pratviel, G., Maveyraud, L. and Bernardes-Genisson, V. Crystal structure of the enoyl-ACP reductase of Mycobacterium tuberculosis (InhA) in the apo-form and in complex with the active metabolite of isoniazid pre-formed by a biomimetic approach. J. Struct. Biol. 190 (2015) 328-337. [PMID: 25891098]

[EC created 2018]

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