Proteolytic inactivation of human factor VIII procoagulant protein by activated human protein C and its analogy with factor V.
Purified human factor VIII procoagulant protein (VIII:C) was treated with purified human activated protein C (APC) and the loss of VIII:C activity correlated with proteolysis of the VIII:C polypeptides. APC proteolyzed all VIII:C polypeptides with mol wt = 92,000 or greater, but not the doublet at mol wt = 79-80,000. These results and our previous thrombin activation studies of purified VIII:C, are analogous with similar studies of factor V and form the basis for the following hypothesis: activated VIII:C consists of heavy and light chain polypeptides [mol wt = 92,000 and mol wt = 79-80,000 (or 71-72,000), respectively] which are similar in Mr to the heavy and light chains of activated factor V. Thrombin activates VIII:C and V by generating these polypeptide chains from larger precursors and APC inactivates both molecules by cleavage at a site located in the heavy chain region of activated VIII:C and V.
D000941:Antigens / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005169:Factor VIII / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008970:Molecular Weight; D012967:Sodium Dodecyl Sulfate; D013917:Thrombin / Q000494:pharmacology; D013997:Time Factors
D000941:Antigens; D012967:Sodium Dodecyl Sulfate; D005169:Factor VIII; D013917:Thrombin