title: Purification and characterization of lebetase, a fibrinolytic enzyme from Vipera lebetina (snake) venom.
abstract: An anticoagulant proteinase, lebetase, was isolated from the venom of Vipera lebetina by gel filtration and anion-exchange chromatography. The proteinase consists of a single polypeptide chain with a molecular weight of 23,700. Amino acid analysis indicates that lebetase contains 214 residues. It consists of several isoforms in the pH range 4.6-5.4, all having fibrinolytic activity. Lebetase hydrolyzes casein, fibrinogen and fibrin, and oxidized insulin B-chain in the positions Ala14-Leu15 and Tyr16-Leu17. Its fibrinolytic activity is inhibited by EDTA and lost upon heating at 70 degrees C for 10 min. The enzyme readily hydrolyzes the A alpha-chain and more slowly the B beta-chain of fibrinogen. In fibrin, the same chains are attacked. Thus, the enzyme is an A alpha, B beta-fibrinogenase. The fibrinolytic activity of lebetase is direct, without any plasminogen activation. E280 1% is 13.0 for lebetase. The enzyme showed low hemorrhagic activity.
authors.affiliation: Laboratory of Bioorganic Chemistry, Estonian Academy of Sciences, Tallinn, U.S.S.R.
authors.forename: E
authors.initials: E
authors.lastname: Siigur
authors.forename: J
authors.initials: J
authors.lastname: Siigur
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D005342:Fibrinolysis; D006470:Hemorrhage / Q000139:chemically induced; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000378:metabolism; D007526:Isoelectric Point; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D014757:Viper Venoms / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D007328:Insulin; D014757:Viper Venoms; D008666:Metalloendopeptidases; C069853:lebetase