title: The effects of plasmin and protein Ca on factor VIII:C and VIII:CAg.
abstract: The effects of various concentrations of plasmin and activated protein C on the factor VIII procoagulant activity (VIII:C) and coagulant antigen (VIII:CAg) were studied in factor VIII concentrates and normal plasma. Small amounts (0.1 CTA U/ml) of plasmin rapidly destroyed VIII:C, and affected, but did not destroy VIII:CAg, in factor VIII concentrates. In normal plasma larger amounts of plasmin (1.8 CTA U/ml) was required to inactivate VIII:C in order to exceed the neutralizing capacity of alpha 2-antiplasmin. VIII:CAg was unchanged indicating a limited proteolysis. The difference between VIII:C and VIII:CAg was found also in urokinase-activated plasma. Activated protein C (5 micrograms/ml), in the presence of Ca2+ and phospholipids, inactivated VIII:C without affecting VIII:CAg in a high purity factor VIII concentrate. Higher concentrations of activated protein C (25 micrograms/ml) caused a slight decrease of VIII:CAg, even in the absence of Ca2+ and phospholipids, but did not change VIII:CAg in normal plasma or serum.
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism*; D004789:Enzyme Activation; D005169:Factor VIII / Q000276:immunology* / Q000378:metabolism; D005341:Fibrinolysin / Q000494:pharmacology*; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D011486:Protein C; D013552:Swine / Q000097:blood; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology
chemical_list: D000941:Antigens; D006023:Glycoproteins; D011486:Protein C; D005169:Factor VIII; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator