[Chemical composition of lipoid anticoagulant and mechanism of its action].

A lipid anticoagulant (ether extract of brain tissue) after repeated treatment with alcohol and acetone contained, mainly, ethanolamine phosphatides and sphingomyelin. The product inhibited the conversion of prothrombin into thrombin due to interaction of the lipid anticoagulant with the substrate (prothrombin). The anticoagulant inhibited also the reaction of thrombin with fibrinogen, producing a kind of "coupling inhibition" as shown by graphical analysis of the inhibition kinetics. A fraction of the anticoagulant, enriched in ethanolamine phosphatides and a fraction, enriched in sphingomyelin, possessed the both types of the activity. But the fraction enriched in the ethanolamine phosphatides inhibited more distinctly the reaction between thrombin and fibrinogen. Kinetics of inhibition of thrombinogenesis and thrombin -- fibrinogen reaction by both anticoagulant fractions and initial anticoagulant was similar.