The structures of the branched fatty acids in the wax esters of vernix caseosa

By combined gas liquid chromatography‐mass spectrometry a series of monomethyl branched fatty acids was found in the fatty acid moiety of the wax esters of vernix caseosa. The methyl branch occurred on the even C‐atoms of chains ranging from C 11 to C 17 (some 43 compounds in all). Except for the iso acids and possibly some of the anteiso acids, these could be formed by replacement of malonyl CoA with a molecule of methyl malonyl CoA at the point of the branch. Smaller amounts of fatty acids also were found with two methyl branches occurring on the even C‐atoms of chains ranging from C 9 to C 15 .