Venom from southern copperhead snake (Agkistrodon Contortrix Contortrix). I. Characterization of a protease that preferentially releases fibrinopeptide B

Abstract A. Shimizu , E. C. Jimenez , J. Takagi , Y. Inada and Y. Saito . Venom from southern copperhead snake ( Agkistrodon contortrix contortrix ). I. Characterization of a protease that preferentially releases fibrinopeptide B. Toxicon 25, 751 – 757, 1987.—Using gel permeation chromatography with high performance liquid chromatograph (HPLC), a highly purified preparation of a protease has been obtained from the venom of the southern copperhead snake ( Agkistrodon contortrix contortrix ). Both gel permeation chromatography with HPLC and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that it had an apparent Mr of 60,000 – 64,000. It consisted of a single polypeptide chain. The activity was inhibited by dithiothreitol. It neither induced platelet aggregation nor activated plasma factor XIII. It cleaved fibrinopeptide B at a rate much faster than fibrinopeptide A from fibrinogen. This specificity was steadily lowered when the incubation temperature was elevated from 0°C to 45°C. Fibrinopeptides were released only at neutral pH.