Studies of von Willebrand factor: effects of different kinds of carbohydrate oxidases, SH-inhibitors and some other chemical reagents.

The effects of several kinds of carbohydrate oxidase, SH-inhibitors and some other chemical reagents on the activities of von Willebrand factor, factor VIII procoagulant and factor VIII-related antigen were studied. Factor VIII procoagulant and von Willebrand factor activities were both inhibited by galactose oxidase, p-hydroxymercuribenzoic acid, 2,4,6-trinitrobenzensulfonic acid and sodium periodate, alpha-Mannosidase, N-ethylmaleimide and phospholipase C inactivated factor VIII procoagulant but not von Willebrand factor activity. Dithiothreitol had little effect on factor VIII procoagulant activity but reduced significantly that of von Willebrand factor. It is suggested that galactose and the thiol and epsilon-aminogroup groups of lysine may play an important role in both factor VIII procoagulant and von Willebrand factor activity. Mannose may be responsible for the factor VIII procoagulant activity but not for the von Willebrand factor activity. The Laurell rocket heights of factor VIII-related antigen rose with increasing concentration of galactose oxidase, 2,4,6-trinitrobenzenesulfonic acid or sodium periodate. Gel filtration experiments showed that factor VIII-related antigen may be dissociated into subunits by galactose oxidase but not by 2,4,6-trinitrobenzenesulfonic acid or sodium periodate.