The Lipids of Milk. II. The Fat Acids of the Sphingo-Myelin-Cerebroside Fraction

Phospholipids occur in all cells and to the extent of approximately 0.034 per cent in the milk of cows.Though their exact function in the animal body is not known, they have been thought to be intimately associated with fat synthesis.Although a minor constituent of food they may prove to be of especial significance.Osborne and Wakeman (1) identified a monoamino-and, presumably, a diamino-phospholipid in milk, and their data indicated that oleic and stearie acids were constituents of the monoamino fraction.Sasaki and Hiratsuka (2) concluded that the lecithin in milk contains myristic and laurie acids ; and the cephalin of milk, palmitic and laurie acids.Kurtz, Jamieson, and Holm (3) isolated the phospholipids from sweet cream buttermilk powder and separated them, on the basis of their solubilities in ether, into two distinct fractions: an ether-soluble lecithin-cephalin fraction, and an ether-insoluble sphingomyelin-eerebroside fraction.Their analysis of the lecithin-cephalin fraction showed that the fat acids consist of 5.2 per cent myristic, 16.1 per cent stearic, 1.8 per cent arachidic, 70.6 per cent oleic and 6.3 per cent of what was presumably a dicostetrenoic acid.The analysis of the sphingomyelin-cerebroside fraction is presented in this paper.