title: Bp-13 PLA2: Purification and Neuromuscular Activity of a New Asp49 Toxin Isolated from Bothrops pauloensis Snake Venom.
abstract: A new PLA2 (Bp-13) was purified from Bothrops pauloensis snake venom after a single chromatographic step of RP-HPLC on μ-Bondapak C-18. Amino acid analysis showed a high content of hydrophobic and basic amino acids and 14 half-cysteine residues. The N-terminal sequence showed a high degree of homology with basic Asp49 PLA2 myotoxins from other Bothrops venoms. Bp-13 showed allosteric enzymatic behavior and maximal activity at pH 8.1, 36°-45°C. Full Bp-13 PLA2 activity required Ca(2+); its PLA2 activity was inhibited by Mg(2+), Mn(2+), Sr(2+), and Cd(2+) in the presence and absence of 1 mM Ca(2+). In the mouse phrenic nerve-diaphragm (PND) preparation, the time for 50% paralysis was concentration-dependent (P < 0.05). Both the replacement of Ca(2+) by Sr(2+) and temperature lowering (24°C) inhibited the Bp-13 PLA2-induced twitch-tension blockade. Bp-13 PLA2 inhibited the contractile response to direct electrical stimulation in curarized mouse PND preparation corroborating its contracture effect. In biventer cervicis preparations, Bp-13 induced irreversible twitch-tension blockade and the KCl evoked contracture was partially, but significantly, inhibited (P > 0.05). The main effect of this new Asp49 PLA2 of Bothrops pauloensis venom is on muscle fiber sarcolemma, with avian preparation being less responsive than rodent preparation. The study enhances biochemical and pharmacological characterization of B. pauloensis venom.
authors: Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), 13083-881 Campinas, SP, Brazil.
authors: Georgina
authors: G
authors: Sucasaca-Monzón
authors: Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), 13083-881 Campinas, SP, Brazil.
authors: Priscila
authors: P
authors: Randazzo-Moura
authors: Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas (UNICAMP), 13083-365 Campinas, SP, Brazil ; Multidisciplinary Research Laboratory, São Francisco University, 12916-350 Bragança Paulista, SP, Brazil.
authors: Thalita
authors: T
authors: Rocha
authors: Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas (UNICAMP), 13083-365 Campinas, SP, Brazil.
authors: Frank Denis
authors: 0000-0001-7638-8847
authors: FD
authors: Torres-Huaco
authors: Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas (UNICAMP), 13083-365 Campinas, SP, Brazil.
authors: Augusto
authors: A
authors: Vilca-Quispe
authors: Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas (UNICAMP), 13083-365 Campinas, SP, Brazil.
authors: Luis Alberto
authors: LA
authors: Ponce-Soto
authors: Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas (UNICAMP), 13083-365 Campinas, SP, Brazil.
authors: Sérgio
authors: S
authors: Marangoni
authors: Department of Biochemistry and Tissue Biology, Institute of Biology, State University of Campinas (UNICAMP), 13083-365 Campinas, SP, Brazil.
authors: Maria Alice
authors: MA
authors: da Cruz-Höfling
authors: Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), 13083-881 Campinas, SP, Brazil.
authors: Léa
authors: L
authors: Rodrigues-Simioni