title: The influence of thrombin on the clotting activity of factor VIII. A study with insolubilized thrombin.
abstract: An investigation of the influence of thrombin on the clotting activity of factor VIII was made. Purified factor VIII and different amounts of thrombin complexed to Sepharose 4 B were mixed and incubated for various periods of time. The factor VIII activities of these incubation mixtures were determined by the one- and two-stage analytical procedures in the presence of the thrombin-sepharose and in its absence following the latter removal from the test sample by filtration. The results so obtained confirm the view that thrombin inactivates factor VIII. Evidences for a thrombin-induced potentiation of the factor VIII activity, seen only in the thrombin-sepharose containing test samples analyzed by the one-stage method, are here interpreted as thrombin-effects peculiar to this factor VIII test system and not as potentiation by thrombin of the factor itself.
mesh_terms: D001777:Blood Coagulation; D005169:Factor VIII; D006801:Humans; D012685:Sepharose / Q000494:pharmacology; D012995:Solubility; D013917:Thrombin / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D005169:Factor VIII; D012685:Sepharose; D013917:Thrombin