10-Methylstearic acid

Branching. For example, stearic acid (18 carbons) and arachidic acid (20 carbons) are both saturated and linear. They melt at 70°C and 75°C, respectively, whereas 10-methylstearic acid melts at 10°C. However, branched fatty acids are rare in living systems and the evolution of synthetic pathways for them has not occurred as a major device for keeping lipids fluid. 

Methylstearic acid 2 C-10 of 9,10-oleic acid M. smegmatis cultures Jaureguiberry et of, 1965... 

Methylstearic acid (+) ( Ci9Hag02 ) + 10-Methylstearic acid (-) ( CigHa)... 

Lennartz, W. j., G. Scheverbrandt, and K. Bloch The biosynthesis of oleic and 10-methylstearic acids in Mycobacterium phlei. J. Biol. Chem. 237, 664 (1962). Lynen, F. Participation of acyl-CoA in carbon chain biosynthesis. J. Cellular Comp. Physiol. 54, 33 (1959). 

Hydrocarbon Analysis. Sediment samples were thawed and mixed to provide a homogeneous sample. Approximately 150 g wet weight was placed in a Soxhlet extraction apparatus and saponified-extracted with benzene /0.5 N KOH-methanol (50/50) (ca. 250 ml total) for 24 hours, or until the extraction solution was clear (6,11,12). An internal standard consisting of ca. 50 ug each of 5,a-androstane and o-terphenyl was added prior to extraction to provide assurance of extraction efficiency, separation of saturated and unsaturated fractions and to provide a standard reference for the gas chromatographic data system. Methylstearate (the methyl ester of stearic acid) was added to select samples to verify saponification efficiency. 

A mid-chain branch occurs in tuberculostearic acid (lOo-methylstearic) present in the lipids of the human tubercle bacillus and in other bacterial lipids. 

For its own purposes, the tuberculosis-causing organism Mycobacterium tuberculosis needs a molecule called 10-methylstearate. It makes this compound from a modified amino acid, 5 -adenosylmethionine, and oleate, a salt of oleic acid (Fig. 3.82). 

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