IUBMB Enzyme Nomenclature


Accepted name: long-chain fatty acid adenylase/transferase FadD26

Reaction: ATP + a long-chain fatty acid + holo-[(phenol)carboxyphthiodiolenone synthase] = AMP + diphosphate + a long-chain acyl-[(phenol)carboxyphthiodiolenone synthase] (overall reaction)
(1a) ATP + a long-chain fatty acid = diphosphate + a long-chain fatty-acyl adenylate ester
(1b) a long-chain fatty-acyl adenylate ester + holo-[(phenol)carboxyphthiodiolenone synthase] = AMP + a long-chain acyl-[(phenol)carboxyphthiodiolenone synthase]

Glossary: phthiocerols = linear carbohydrates containing one methoxyl group, one methyl group, and two secondary hydroxyl groups that serve as a backbone for certain lipids and glycolipids found in many species of Mycobacteriaceae
arachidate = icosanoate
behenate = docosanoate
lignocerate= tetracosanoate

Other name(s): FadD26

Systematic name: long-chain fatty acid:holo-[(phenol)carboxyphthiodiolenone synthase] ligase (AMP-forming)

Comments: The enzyme, present in pathogenic species of mycobacteria, participates in the pathway for biosynthesis of phthiocerols. It catalyses the adenylation of the long-chain fatty acids arachidate (C20) or behenate (C22) [1] and potentially the very-long-chain fatty acid lignocerate (C24) [2]. The activated fatty acids are then loaded to EC, (phenol)carboxyphthiodiolenone synthase.

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


1. Azad, A.K., Sirakova, T.D., Fernandes, N.D. and Kolattukudy, P.E. Gene knockout reveals a novel gene cluster for the synthesis of a class of cell wall lipids unique to pathogenic mycobacteria. J. Biol. Chem 272 (1997) 16741-16745. [PMID: 9201977]

2. Simeone, R., Leger, M., Constant, P., Malaga, W., Marrakchi, H., Daffe, M., Guilhot, C. and Chalut, C. Delineation of the roles of FadD22, FadD26 and FadD29 in the biosynthesis of phthiocerol dimycocerosates and related compounds in Mycobacterium tuberculosis. FEBS J. 277 (2010) 2715-2725. [PMID: 20553505]

3. Vergnolle, O., Chavadi, S.S., Edupuganti, U.R., Mohandas, P., Chan, C., Zeng, J., Kopylov, M., Angelo, N.G., Warren, J.D., Soll, C.E. and Quadri, L.E. Biosynthesis of cell envelope-associated phenolic glycolipids in Mycobacterium marinum. J. Bacteriol. 197 (2015) 1040-1050. [PMID: 25561717]

[EC created 2019]

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