title: Isolation and biochemical characterization of hemorrhagic toxin f from the venom of Crotalus atrox (western diamondback rattlesnake).
abstract: Hemorrhagic toxin f (HT-f) was isolated from Crotalus atrox (Western Diamondback Rattlesnake) venom by a five-step purification procedure. Homogeneity was established by the formation of a single band in acrylamide gel electrophoresis, isoelectric focusing, and sodium dodecyl sulfate (SDS)-electrophoresis. HT-f has a molecular weight of 64,000 and contains 572 amino acid residues. It contains 1 mol of zinc per mol of protein. Zinc is essential for both hemorrhagic and proteolytic activities. HT-f possesses proteolytic activity hydrolyzing the Val-Asn, Gln-His, Leu-Cys, His-Leu, Ala-Leu, and Tyr-Leu bonds of oxidized insulin B chain. HT-f did not coagulate fibrinogen to fibrin, yet it did hydrolyze the gamma chain of fibrinogen without affecting either the A alpha or B beta chains. This is the first time that a hemorrhagic toxin was shown to have fibrinogenase activity. HT-f was shown to differ immunologically from other hemorrhagic toxins such as HT-a and HT-c. HT-f also possesses lethal toxicity. When zinc was removed the apo-HT-f lost its lethal toxicity. HT-f produced not only local hemorrhage in the skin and muscle, but also produced systemic hemorrhage in internal organs such as the intestine, kidney, lung, heart, and liver.
mesh_terms: D000596:Amino Acids / Q000302:isolation & purification; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D003435:Crotalid Venoms / Q000032:analysis* / Q000302:isolation & purification; D005342:Fibrinolysis; D007120:Immunochemistry; D007928:Lethal Dose 50; D008666:Metalloendopeptidases; D051379:Mice; D008970:Molecular Weight; D009132:Muscles / Q000187:drug effects / Q000473:pathology; D010447:Peptide Hydrolases; D014118:Toxins, Biological / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D003435:Crotalid Venoms; D014118:Toxins, Biological; D010447:Peptide Hydrolases; D008666:Metalloendopeptidases; C041374:atrolysin F