Chemical Nature of Human Brain Thromboplastin

Abstract

IN 1958, Hecht et al.¹ prepared a thromboplastin (TP) from rabbit brain dried with acetone according to Quick². Inactive fractions containing protein with respect to blood coagulation were separated by repeated ultracentrifugation from a transparent, biuret negative lipid material which possessed the properties of a fully active thromboplastin. In a similar manner, Deutsch et al.³ prepared a purified, biuret negative TP from human brain. On further treatment with pyridine, however, two fractions were obtained. One of these was soluble in pyridine, free of protein, and exhibited only a weak promotion of clotting effect as is commonly the case with lipid activators⁴. It was considered to be the lipid moiety of the TP. The other fraction was insoluble in pyridine, inactive in blood coagulation, and according to Deutsch et al.³ the protein moiety of the TP. The authors assumed that the rabbit brain TP of Hecht et al.¹ was identical with their preparation, and was thus a compound containing protein as well.