THE EFFECT OF CERTAIN SULFUR COMPOUNDS ON THE COAGULATION OF BLOOD

Abstract

Three lines of investigation were undertaken to explain the inhibiting action of cysteine on the coagulation of blood. (a) In vivo expts. with whole blood. Cysteine, taurine and taurocholic acid produced marked inhibition; glycine, alanine, cysteic acid and methionine had no effect. (b) In vitro expts. with the isolated components of the blood clotting system. Tissue factor, Ca, thrombin and fibrinogen are little affected or not affected at all when exposed to the action of cysteine. When cysteine is added to a solution of prothrombin, the subsequent clot-ting is markedly inhibited. Other reducing substances, e.g., ascorbic acid and phenosaphranine, had no such effect. (c) In vivo expts. in human subjects. Cysteine and methionine, ingested and injected intraven., delayed both the bleeding time (Ivy method) and the coagulation time (8 mm. tube method).