Biochemical characterization of a thrombin-like enzyme and a fibrinolytic serine protease from snake (Agkistrodon saxatilis) venom

A thrombin-like enzyme and a fibrinolytic serine protease were purified to homogeneity from the venom of a Korean snake Agkistrodon saxatilis emeliano v. Both the purified enzymes migrated as a single protein band correspondin g to 39 kDa in SDS-PAGE. However, the molecular mass was reduced to 28 kDa by enzymatic removal of the N-linked carbohydrates in those two different e nzyme species. Although the thrombin-like enzyme and the fibrinolytic prote ase show homologous features in their molecular sizes and N-terminal amino acid sequences, yet they can be clearly distinguished from each other in te rms of substrate specificity, susceptibility to inhibitors and fibrinogen d egradation. It is postulated that these two enzymes are capable of function ing in a cooperative manner to effectively remove fibrinogen and consequent ly to reduce the blood viscosity. (C) 2000 Elsevier Science Ltd. All rights reserved.