Biochemical characterization of fibrinogenolytic serine proteinases from Vipera lebetina snake venom

Two glycosylated serine fibrinogenases isolated from Vipera lebetina venom have homologous N-terminal sequences and antigenic determinants but can be clearly differentiated according to substrate specificity, glycosylation le vels, molecular mass and fibrinogen degradation. alpha -Fibrinogenase has n o homolog among known serine proteinases. It has N-terminal similarity with snake venom arginine esterases but does not hydrolyze the esters of argini ne, lysine and tyrosine. The enzyme has strong proteolytic activity and deg rades alpha -chain of fibrinogen altering its clottability by thrombin. bet a -Fibrinogenase is a typical arginine esterase which hydrolyzes esters and amides of arginine and attacks the beta -chain of fibrinogen. (C) 2001 Els evier Science Ltd. All rights reserved.