title: Isolation of a protein C activator from southern copperhead venom.
abstract: A protease from the venom of the Southern Copperhead snake (Agkistrodon contortrix contortrix) that activates protein C was purified to homogeneity by a combination of sulfopropyl (SP)-Sephadex C-50, Sephadex G-150 and Mono-S column chromatography. The purified enzyme is a glycoprotein, and migrated as a single band in sodium dodecylsulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 37,000 under non-reducing conditions. Upon reduction with 2-mercaptoethanol, the enzyme exhibited a Mr of 40,000. The purified enzyme prolonged the clotting time of human plasma in a dose- and temperature-dependent manner. Purified bovine protein C was completely activated within 10 minutes upon incubation with the purified protease at a 1:500 enzyme: substrate ratio. This reaction was markedly inhibited by calcium ions. The purified venom protein C activator had no effect on human fibrinogen.
mesh_terms: D000818:Animals; D003435:Crotalid Venoms / Q000032:analysis*; D004789:Enzyme Activation; D008970:Molecular Weight; D009842:Oligopeptides / Q000302:isolation & purification*; D011486:Protein C / Q000302:isolation & purification*
chemical_list: D003435:Crotalid Venoms; D009842:Oligopeptides; D011486:Protein C; C047135:protein C activator peptide