The enzyme, characterized from mycobacteria, is loaded with a long-chain acyl moiety by EC 126.96.36.199, long-chain fatty acid adenylyltransferase FadD28, and elongates it by incorporation of three or four methylmalonyl (but not malonyl) residues, to form tri- or tetramethyl-branched fatty-acids, respectively, such as 2,4,6,8-tetramethyloctacosanoate (C32-mycocerosate). Since the enzyme lacks a thioesterase domain, the product remains bound and requires additional enzyme(s) for removal. Even though the enzyme can accept C6 to C20 substrates in vitro, it prefers to act on C14-C20 substrates in vivo.
EC 188.8.131.52 created 1989, modified 2016, modified 2017
Fatty acid biosynthesis in Mycobacterium tuberculosis var. bovis Bacillus Calmette-Guerin. Purification and characterization of a novel fatty acid synthase, mycocerosic acid synthase, which elongates n-fatty acyl-CoA with methylmalonyl-CoA.