Characterization of a thrombin-like enzyme from the venom of Trimeresurus jerdonii

From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, c alled jerdonobin. was purified by DEAF A-25 ion-exchange chromatography, Se phadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypep tide chain with a molecular weight of 38,000. The NH2-terminal amino acid s equence of jerdonobin has great homology with venom thrombin-like enzymes d ocumented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg, The fibrinopeptides released, identified by HPLC consisted of fibrinopeptid e A and a small amount of fibrinopepide B. The activities of the enzyme wer e inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-gua nidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it. indicating it is venom serine protease. (C) 2000 Elsevier Science Ltd. All rights reserved.