text: Tuberculostearic acid (D-10-Methylstearic acid) is a saturated fatty acid that is known to be produced by Mycobacterium spp. and two species of Streptomyces.  It is formed from the precursor oleic acid (a monounsaturated fatty acid). After oleic acid is esterified to a phospholipid, S-adenosyl-methionine donates a methyl group to the double bond of oleic acid. This methylation reaction forms the intermediate 10-methylene-octadecanoyal. Successive reduction of the residue, with NADPH as a cofactor, results in 10-methylstearic acid