Effects of Plasmin on Human Factor VIII (AHF)

Highly purified, fibrinogen-free human factor VIII was incubated with plasmin, and the liberated split products of the factor VIII were analyzed by gel filtration, acrylamide gel electrophoresis, bioassay, and for immunologic reactivity. At least three fragments retaining different antigenic determinants are released from the factor VIII after prolonged digestion and at least three new fragments are seen in acrylamide gel electrophoresis. The split products were not anticoagulant in the factor VIII activity assay. In fact, the breakdown products in the hydrolysate increased the factor VIII activity of normal plasma mixed with it. Therefore, it is not likely that the factor VIII split products formed in fibrinolytic states contribute actively to the hemorrhagic diathesis.