Purification, characterization and anticoagulant activity of a proteolytic enzyme from Vespa orientalis venom

The anticoagulant effect of Vespa orientalis venom sac extract (VSE) was attributed to a proteolytic process, involving mainly coagulation factors VIII and IX [Joshua, H., Ishay, J., 1975. Toxicon 13, 11-20; Korenberg et al., 1988. Toxicon 26, 1169-1176]. Preliminary purification of the proteolytic activity showed the presence of three separate proteases. One of which, protease I, was purified. The purified enzyme migrated as a double band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). The molecular weights of the bands, under reduced conditions were 42 and 44 kD. Both bands retained activity after the electrophoretic run. The enzyme hydrolyses bovine factor IX (BFIX), factor X (BFX) and prothrombin. The pH optimum for the degradation of BFIX was 7.0 and its isoelectric point is above pH 10. The amino acid composition of the protease was determined.