Biochemical Characterization of a PLA2 Btae TX-I Isolated from Bothriopsis taeniata Snake Venom: A Pharmacological and Morphological Study
- *Corresponding Author:
- Dr. Maria Alice da Cruz-Höfling
Department of Histology and Embryology
Institute of Biology, State University of Campinas (UNICAMP)
P.O. Box 6109, Zip Code 13083-865, Campinas, SP, Brazil
Fax: 55 19 3521-6374
Tel: +55 19 21065321
E-mail: [email protected]
Received Date: March 31, 2014; Accepted Date: May 19, 2014; Published Date: May 24, 2014
Citation: Romero-Vargas FF, Rocha T, Cruz-Höfling MA, Rodrigues-Simioni L, Ponce-Soto LA et al. (2014) Biochemical Characterization of a PLA2 Btae TX-I Isolated from Bothriopsis taeniata Snake Venom: A Pharmacological and Morphological Study. J Clin Toxicol 4:197. doi: 10.4172/2161-0495.1000197
Copyright: © 2014 Romero-Vargas FF et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
In this research a preliminary identification and biochemical and biological characterization of a PLA2 (Btae TX-I) from the venom of a viperid snake, Bothriopsis taeniata (Speckled forest pit viper) were obtained. Btae TX-I was purified by two chromatographic steps, molecular exclusion chromatography followed by analytical chromatography reverse phase HPLC. Molecular mass behaved as a homogeneous single chain protein on SDS–PAGE, confirmed by MALDI-TOF spectrometry, indicating a molecular mass of 13889.98 Da. Tryptic peptides were determined in tandem mass spectrometry and showed similarity with other myotoxic PLA2s. Btae TX-I belongs to the Asp49 PLA2 class, is enzymatically active in presence of a synthetic substrate and shows a minimum sigmoidal behavior, reaching its maximal activity at pH 8.0 and 35–45°C. PLA2 activity in presence of Mn2+, Mg2+, Cd2+ and Zn2+ was reduced either in presence or absence of Ca2+, suggesting that the arrangement of the catalytic site presents an exclusive structure for Ca2+. Crotalic crotapotins from rattlesnake venom has significantly inhibited (p<0.05) the enzymatic activity of Btae TX-I. In ex vivo experiment, Btae TX-I caused partial blockade of the neuromuscular transmission in chick biventer cervicis preparations in a similar way to other Bothrops species. Btae TX-I also inhibited contractures in the upper concentration (50 μg) to exogenous KCl (20 mM). Histological analysis of the biventer cervicis incubated with Btae TX-I showed that just the highest Btae TX-I PLA2 dose (50 μg) caused almost 27.4 ± 0.3% damaged fibers. The results give evidence that the main effect of type Asp49 Btae TX-I PLA2 from Bothriopsis taeniata is at the post-synaptic site.