The effects of plasmin and protein Ca on factor VIII:C and VIII:CAg

Research output: Contribution to journalArticle


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.


Research areas and keywords


  • Animals, Antigens, Enzyme Activation, Factor VIII, Fibrinolysin, Glycoproteins, Humans, In Vitro Techniques, Protein C, Swine, Urokinase-Type Plasminogen Activator, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)41-50
Number of pages10
JournalThrombosis Research
Issue number1
Publication statusPublished - 1983 Jul 1
Publication categoryResearch