POLAR LIPIDS IN BOVINE MILK .I. LONG-CHAIN BASES IN SPHINGOMYELIN

Sphingomyelin was isolated from spray-dried buttermilk powder, and was converted to ceramide by the action of phospholipase C (EC 3.1.4.3). Ceramide was separated by preparative thin-layer chromatography into fractions containing (I) saturated dihydroxy bases and normal fatty acids, (II) unsaturated dihydroxy bases and normal fatty acids, and (III) dihydroxy bases and polar (hydroxy ?) fatty acids. The compositions of the fatty acids in ceramides I and II were almost identical. Long-chain bases from the ceramide fractions were oxidised with periodate, and the aldehydes produced were analysed by gas-liquid chromatography. The aldehydes were also reduced to alcohols and analysed by combined gas-liquid chromatography and mass spectrometry. Altogether 31 long-chain bases were identified, consisting of saturated dihydroxy bases with n-C12-20, iso C17-20, and anteiso C17-19 structures, and unsaturated dihydroxy bases with n-C12-20, iso-C14-19, and anteiso-C15,17,19 structures. © 1969.