title: L-amino acid oxidase from Vipera lebetina venom: isolation, characterization, effects on platelets and bacteria.
abstract: The L-amino acid oxidase from Vipera lebetina venom was purified to homogeneity using combination of size exclusion, ion exchange and hydrophobic chromatography. The monomeric molecular mass of the homodimeric enzyme is 60.9kDa. The N-terminal and the tryptic peptides share high homology with other snake venom L-amino acid oxidases. The enzyme displays high specificity towards hydrophobic L-amino acids, the best substrates are L-Met, L-Trp, L-Leu followed by L-His, L-Phe, L-Arg and L-Ile. Six substrates-Gly, L-Ser, L-Thr, L-Pro, L-Cys, L-Asp--were not oxidized. The enzyme has antimicrobial activity inhibiting the growth of both Gram-negative and Gram-positive bacteria. V. lebetina LAAO dose-dependently inhibited platelet aggregation induced by ADP or collagen. In case of ADP-induced aggregation the inhibitory effect was more pronounced on the second wave of aggregation.
authors.affiliation: National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia.
authors.forename: Külli
authors.initials: K
authors.lastname: Tõnismägi
authors.forename: Mari
authors.initials: M
authors.lastname: Samel
authors.forename: Katrin
authors.initials: K
authors.lastname: Trummal
authors.forename: Gunilla
authors.initials: G
authors.lastname: Rönnholm
authors.forename: Jüri
authors.initials: J
authors.lastname: Siigur
authors.forename: Nisse
authors.initials: N
authors.lastname: Kalkkinen
authors.forename: Ene
authors.initials: E
authors.lastname: Siigur
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D001792:Blood Platelets / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D050830:L-Amino Acid Oxidase / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010974:Platelet Aggregation / Q000187:drug effects; D016415:Sequence Alignment; D013045:Species Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013379:Substrate Specificity; D014757:Viper Venoms / Q000201:enzymology*; D017819:Viperidae
chemical_list: D014757:Viper Venoms; D050830:L-Amino Acid Oxidase