two aspects of the activation of factor x by the intrinsic clotting pathway have been studied in purified human systems , in the presence of either purified phosphatidylserine : phosphatidylcholine vesicles ( ps : pc ) or platelets activated with ionophore a23187 : ( 1 ) the activation of factor viii by factor xa and by thrombin , and ( 2 ) the activation of factor x by the factor ixa/viiia complex .
C0015520
factor xa
C0015518
factor x