Purified platelet phospholipids and blood coagulation.

By JOHN H. FERGUSON, AARON J. MARCUS AND A. JEAN ROBINSON P LATELET PHOSPHATIDYLSERINE ( PS ) and phosphatidylethanolamine (PE) have been successfully isolated and purified1”8 by applying methods worked out by Rouser and colleagues4 for the corresponding brain phospholipids. With the modern evolution5t of clotting tests, applicable to research on the role of phosphatides7’8 in blood coagulation, an opportunity was offered for a collaborative effort to study the purified platelet phospholipids and to compare them with brain cephalin in these test systems. A significant new bioassay has been validated and is supplemented by data concerning altering reactivities and effects of mixtures of these phosphatides. Comparisons are made between the thromboplastic enzyme methods and the other tyI)eS of clotting tests which seek a solution to these complex problems.