Thrombin proteolysis of purified factor viii procoagulant protein: correlation of activation with generation of a specific polypeptide.
Factor VIII procoagulant protein (VIII:C) purified from commercial factor VIII concentrate contained multiple polypeptides ranging in mol wt from 79,000 to 188,000, all of which were removed from solution by a monoclonal anti-VIII:C antibody specific for a thrombin-sensitive epitope. In a time-course digest of the purified VIII:C using a trace amount of purified human alpha-thrombin, changes occurred in all VIII:C polypeptides during the activation and inactivation of VIII:C activity. The generation and destruction of a mol wt 92,000 polypeptide paralleled the increase and decrease in VIII:C activity, suggesting that this polypeptide represents an activated form. These results provide the basis for a working hypothesis for the mechanism of thrombin activation of VIII:C.
D000911:Antibodies, Monoclonal / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D005169:Factor VIII / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D010452:Peptide Biosynthesis; D012967:Sodium Dodecyl Sulfate; D013917:Thrombin / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D012967:Sodium Dodecyl Sulfate; D005169:Factor VIII; D013917:Thrombin