Heterogeneity of human factor VIII. I. Characterization of factor VIII present in the supernatant of cryoprecipitate.
Recent observations suggest that plasma F VIII consists of a series of molecules with different molecular weights. The data described in this paper suggest that sup F VIII represents the molecules with relatively low molecular weights whereas the molecules with the highest molecular weights appear in cryo F VIII. Sup F VIII was associated with VIII:C and VIIIR:Ag, but ristocetin cofactor activity was lacking. Although the immunoprecipitation characteristics of sup F VIII with rabbit antifactor VIII were different from those of cryo F VIII, immunological identity was observed in immunodiffusion and crossed immunoelectrophoresis. In 0.8M NaCl sup F VIII dissociated into VIIIR:Ag of relatively high molecular weight and VIII:C of low molecular weight. No indications were obtained that the presence of sup F VIII was the result of proteolytic degradation of factor VIII. VIII:C of sup F VIII was more labile in vitro than VIII:C in plasma. It could be activated by traces of thrombin in a way similar to plasma F VIII. In patients with classic von Willebrand's disease relatively more VIII:C remained in the supernatant after cryoprecipitation of plasma.
D011232:Chemical Precipitation; D002850:Chromatography, Gel; D003450:Cryoglobulins; D005169:Factor VIII / Q000276:immunology / Q000302:isolation & purification; D006467:Hemophilia A / Q000097:blood; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007610:Kallikreins / Q000494:pharmacology; D009994:Osmolar Concentration; D013917:Thrombin / Q000494:pharmacology
D003450:Cryoglobulins; D005169:Factor VIII; D007610:Kallikreins; D013917:Thrombin