[Effect of phosphatidyl serine on conversion of fibrinogen to fibrin]

Phosphatidyl serine inhibited the conversion of fibrinogen into fibrin, catalyzed by thrombin, following the pattern of coupling inhibition. The inhibition was caused by the property of phosphatidyl serine of forming an exhibiting low activity complex with thrombin as well as by interaction of the lipoid with monomeric fibrin; as a result of this process phosphatidyl serine inhibited both enzymatic and non-enzymatic pathways of the fibrin formation. Administration of phosphatidyl serine into animal circulation led to a decrease in fibrinogen consumption, provoked by simultaneous injection of thrombin. Phosphatidyl serine appears to serve as a circulating anticoagulant.