title: Kallikrein-like proteinase from bushmaster snake venom.
abstract: A kallikrein-like proteinase of Lachesis muta muta (bushmaster) venom, designated LV-Ka, was purified by gel filtration and anion exchange chromatographies. Physicochemical studies indicated that the purified enzyme is a 33 kDa monomeric glycoprotein, the Mr of which fell to 28 kDa after deglycosylation with PNGase F. Approximately 77% of the protein sequence was determined by sequencing the various fragments derived from digestions with endoproteases. The partial sequence obtained suggests that LV-Ka is of a similar size to other serine proteinases (i.e., approximately 234 amino acid residues). Sequence studies on the NH2-terminal region of the protein indicate that LV-Ka shares a high degree of sequence homology with the kallikrein-like enzymes EI and EII from Crotalus atrox, with crotalase from Crotalus adamanteus and significant homology with other serine proteinases from snake venoms and vertebrate serum enzymes. LV-Ka showed kallikrein-like activity, releasing bradikinin from kininogen as evidenced by guinea pig bioassay. In addition, intravenous injection of the proteinase (0.8 microg/g) was shown to lower blood pressure in experimental rats. In vitro, the isolated proteinase was shown to have neither fibrin(ogeno)lytic activity nor coagulant effect. LV-Ka was active upon the kallikrein substrates S-2266 and S-2302 (specific activity=13.0 and 31.5 U/mg, respectively; crude venom=0.25 and 6.0 U/mg) but had no proteolytic effect on dimethylcasein and insulin B chain. Its enzymatic activity was inhibited by NPGB and PMSF, indicating that the enzyme is a serine proteinase. Interestingly, one of the other reactions catalyzed by plasma kallikrein, the activation of plasminogen was one of the activities exhibited by LV-Ka.
authors.affiliation: Centro de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro # 80, Belo Horizonte, MG 30510-010, Brazil.
authors.forename: Liza F
authors.initials: LF
authors.lastname: Felicori
authors.forename: Christiane T
authors.initials: CT
authors.lastname: Souza
authors.forename: David T
authors.initials: DT
authors.lastname: Velarde
authors.forename: Arinos
authors.initials: A
authors.lastname: Magalhaes
authors.forename: Alvair P
authors.initials: AP
authors.lastname: Almeida
authors.forename: Suely
authors.initials: S
authors.lastname: Figueiredo
authors.forename: Michael
authors.initials: M
authors.lastname: Richardson
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Diniz
authors.forename: Eladio F
authors.initials: EF
authors.lastname: Sanchez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D004797:Enzyme-Linked Immunosorbent Assay; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007610:Kallikreins / Q000302:isolation & purification* / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D051381:Rats; D013379:Substrate Specificity; D014757:Viper Venoms / Q000737:chemistry*; D017819:Viperidae
chemical_list: D014757:Viper Venoms; D007610:Kallikreins