Author | Freitas, A. P. | |
Author | Santos, C. R. | |
Author | Sarcinelli, P. N. | |
Author | Silva Filho, M. V. | |
Author | Hauser-Davis, R. A. | |
Author | Lopes, R. M. | |
Access date | 2017-03-01T15:49:28Z | |
Available date | 2017-03-01T15:49:28Z | |
Document date | 2016 | |
Citation | FREITAS, A. P. et al. Evaluation of a Brain Acetylcholinesterase Extraction Method and Kinetic Constants after Methyl-Paraoxon Inhibition inThree Brazilian Fish Species. Plos One, v.11, n.9, e0163317, 10p, Sept. 2016. | pt_BR |
ISSN | 1932-6203 | pt_BR |
URI | https://www.arca.fiocruz.br/handle/icict/17910 | |
Language | eng | pt_BR |
Publisher | Public Library of Science | pt_BR |
Rights | open access | pt_BR |
Subject in Portuguese | Peixes | pt_BR |
Subject in Portuguese | Brasil | pt_BR |
Subject in Portuguese | Acetylcholinesterase | pt_BR |
Subject in Portuguese | Inibidores da Colinesterase | pt_BR |
Subject in Portuguese | Sistema nervoso | pt_BR |
Title | Evaluation of a Brain Acetylcholinesterase Extraction Method and Kinetic Constants after Methyl-Paraoxon Inhibition in Three Brazilian Fish Species | pt_BR |
Type | Article | pt_BR |
DOI | 10.1371/journal.pone.0163317 | |
Abstract | Acetylcholinesterase (AChE) is an important enzyme in the control of the neuronal action potential and sensitive to organophosphate inhibition. Brain fish AChE is less sensitive to organophosphate inhibition than AChE from terrestrial animals, although this sensitivity is variable among species and has not yet been fully evaluated in fish species. In this setting, inhibition kinetic constants for progressive irreversible inhibition of brain acetylcholinesterase due to methyl-paraoxon exposure were determined in three fish species (Mugil liza, Genidens genidens and Lagocephalus laevigatus) and hen (Gallus domesticus). Enzyme extraction using a detergent was shown to be adequate, and samples presented activity inhibition in high substrate concentrations and suppression of inhibition by methyl-paraoxon in the presence of the substrate, similar to kinetic patterns from purified enzyme preparations. Catfish (G. genidens) AChE presented the highest sensitivity among the evaluated fish species (IC50 = 1031.20 nM ± 63.17) in comparison to M. liza and L. laevigatus (IC50: 2878.83 ± 421.94 and 2842.5 ± 144.63 nM respectively). The lower dissociation constant (Kd = 20.3 ± 2.95 μM) of catfish AChE showed greater enzyme affinity for methyl-paraoxon, explaining this species higher sensitivity to organophosphates. Hen AChE presented higher ki (900.57 ± 65.3 mM-1min-1) and, consequently, greater sensitivity to methyl-paraoxon, explained by a lower Kd (0.6 ± 0.13 μM). Furthermore, hen AChE did not differentiate between the propionylthiocholine and acetylthiocholine substrates, indicating easier access of methyl-paraoxon to the hen enzyme activity site. The results obtained herein indicate a suitable extraction of AChE and, despite different inhibition kinetic constants, demonstrate that fish AChE is less sensitive to methyl-paraoxon, probably due to reduced access to the catalytic center which provides greater enzyme substrate selectivity. | pt_BR |
Affilliation | Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sérgio Arouca. Centro de Estudos da Saúde do Trabalhador e Ecologia Humana, Rio de Janeiro, RJ, Brasil . | pt_BR |
Affilliation | Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sérgio Arouca. Centro de Estudos da Saúde do Trabalhador e Ecologia Humana, Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Bioquímica Médica Leopoldo de Meis. Rio de Janeiro, RJ, Brasil. | pt_BR |
Affilliation | Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sérgio Arouca. Centro de Estudos da Saúde do Trabalhador e Ecologia Humana, Rio de Janeiro, RJ, Brasil. | pt_BR |
Affilliation | Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sérgio Arouca. Centro de Estudos da Saúde do Trabalhador e Ecologia Humana, Rio de Janeiro, RJ, Brasil | pt_BR |
Affilliation | Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sérgio Arouca. Centro de Estudos da Saúde do Trabalhador e Ecologia Humana, Rio de Janeiro, RJ, Brasil | pt_BR |
Affilliation | Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Comunicação Celular. Rio de Janeiro, RJ, Brasil. | pt_BR |
Subject | fish brain AChE | pt_BR |
Subject | Brazil | pt_BR |
Subject | Brain Acetylcholinesterase | pt_BR |
Subject | methyl-paraoxon | pt_BR |
Subject | Cholinesterase Inhibitors | pt_BR |