[Mechanism of thrombinogenesis inhibition by phosphatidyl serine]

The graphical analysis of the thrombinogenesis phosphatidyl serine inhibition kinetics accompanied by the prothrombin complex activation by factors III or Xa in the presence of calcium ions evidences for the inhibitor coupling with the process substrate, prothrombin. Evidently, phosphatidyl serine inhibits only the second stage of thrombinogenesis--the interaction of factor Xa with prothrombin, and does not affect the activation of factor X. It is also established that phosphatidyl serine evoke no decrease in the intensity of the factor Xa and prothrombin coupling with factor III and forms no complexes with factor Xa. Therefore, the interaction of factor Xa-prothrombin realized due to appearance of the phosphatidyl serine-prothrombin low-active complex is the only object of the inhibitory effect of phosphatidyl serine on thrombogenesis.