title: Purification and properties of a kininogenin from the venom of Lachesis muta (bushmaster).
abstract: An acidic kininogenin from Lachesis muta snake venom was purified to apparent homogeneity by a combination of gel filtration, isoelectric focusing and preparative gel electrophoresis. It was shown to be a highly stable serine protease (mol. wt 27,900; pI 5.4) capable of releasing bradykinin from low mol. wt bovine kininogen and of cleaving some synthetic chromogenic peptides with the following catalytic efficiencies (Kcat/Km, M-1.sec-1): N-benzoyl-Phe-Val-Arg-p-nitroanilide (1.92 x 10(4)); H-D-Val-Leu-Arg-p-nitroanilide (1.55 x 10(4)); N-acetyl-Phe-Arg-p-nitroanilide (3.98 x 10(2)); no hydrolysis was observed with N-benzoyl-Arg-p-nitroanilide. A marked and sustained hypotensive effect was recorded following i.v. injection of purified kininogenin into rats. Tachyphylaxis was observed after repeated i.v. injection of the enzyme, a phenomenon accompanied by a decrease of only 15% in the total circulating rat kininogen. Both the in vivo action and the enzymatic properties of the L. muta kininogenin indicate that this enzyme might be helpful for understanding the kinin-kininogen system.
authors.affiliation: Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Diniz
authors.forename: E B
authors.initials: EB
authors.lastname: Oliveira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001920:Bradykinin / Q000378:metabolism; D002850:Chromatography, Gel; D003435:Crotalid Venoms / Q000737:chemistry / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D007526:Isoelectric Point; D007704:Kininogens / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D051381:Rats; D012697:Serine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D003435:Crotalid Venoms; D007704:Kininogens; D010455:Peptides; D012697:Serine Endopeptidases; D001920:Bradykinin