The phospholipids of butter and their effect on blood coagulation

Abstract

The addition of butter to plasma shortened the Stypven clotting time of human plasma by over 75% and butter was more active than any other fat tested. A preliminary separation of butter lipids indicated that the thromboplastic activity was confined to the phospholipids originally bound to the proteins of butter. Butter phospholipids were separated by chromatography on silicic acid columns by stepwise and continuous gradient elution techniques, with methanol-chloroform mixtures. A simple method of obtaining an approximately linear gradient is described which may be of general use in the separation of phospholipid mixtures. Ten major phospholipids have been detected in butter and most of these have been identified by paper chromatography and chemical analysis of the intact lipids and their hydrolysis products. A comparison of the Stypven clotting activities of the butter-phos-pholipid fractions with that of synthetic L-[alpha]-dimyristoylphosphatidyl-ethanolamine has shown that a number of these fractions are far more active than the synthetic compound. The most active butter phospholipid (compound X), has not yet been identified.