Laboratório de Imunopatologia Keizo Asami-LIKA and Laboratório de Enzimologia-LABENZ, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife-PE, Brazil.
Sci Total Environ. 2012 Dec 15;441:141-50. doi: 10.1016/j.scitotenv.2012.09.058. Epub 2012 Nov 6.
Monitoring of pesticides based on acetylcholinesterase (AChE; EC 3.1.1.7) inhibition in vitro avoids interference of detoxification defenses and bioactivation of some of those compounds in non-target tissues. Moreover, environmental temperature, age and stress are able to affect specific enzyme activities when performing in vivo studies. Few comparative studies have investigated the inter-specific differences in AChE activity in fish. Screening studies allow choosing the suitable species as source of AChE to detect pesticides in a given situation. Brain AChE from the tropical fish: pirarucu (Arapaima gigas), cobia (Rachycentron canadum) and Nile tilapia (Oreochromis niloticus) were characterized and their activities were assayed in the presence of pesticides (the organophosphates: dichlorvos, diazinon, chlorpyrifos, temephos, tetraethyl pyrophosphate- TEPP and the carbamates: carbaryl and carbofuran). Inhibition parameters (IC₅₀ and Ki) for each species were found and compared with commercial AChE from electric eel (Electrophorus electricus). Optimal pH and temperature were found to be 8.0 and 35-45 °C, respectively. A. gigas AChE retained 81% of the activity after incubation at 50 °C for 30 min. The electric eel enzyme was more sensitive to the compounds (mainly carbofuran, IC₅₀ of 5 nM), excepting the one from A. gigas (IC₅₀ of 9 nM) under TEPP inhibition. These results show comparable sensitivity between purified and non-purified enzymes suggesting them as biomarkers for organophosphorus and carbamate detection in routine environmental and food monitoring programs for pesticides.
基于乙酰胆碱酯酶（AChE；EC 3.1.1.7）抑制的体外监测可避免解毒防御和某些化合物在非靶组织中的生物活化的干扰。此外，在进行体内研究时，环境温度、年龄和应激能够影响特定的酶活性。少数比较研究调查了鱼类中 AChE 活性的种间差异。筛选研究允许选择合适的物种作为 AChE 的来源，以在特定情况下检测农药。从热带鱼：巨骨舌鱼（Arapaima gigas）、军曹鱼（Rachycentron canadum）和尼罗罗非鱼（Oreochromis niloticus）的大脑 AChE 进行了表征，并在存在农药的情况下测定了它们的活性（有机磷：敌敌畏、二嗪农、毒死蜱、硫丹、四乙基焦磷酸酯-TEPP 和氨基甲酸酯：西维因和呋喃丹）。发现了每种物种的抑制参数（IC₅₀和 Ki），并与电鳗（Electrophorus electricus）的商业 AChE 进行了比较。发现最佳 pH 值和温度分别为 8.0 和 35-45°C。在 50°C 下孵育 30 分钟后，A. gigas AChE 保留了 81%的活性。电鳗酶对化合物（主要是呋喃丹，IC₅₀为 5 nM）更敏感，除了 A. gigas 酶（TEPP 抑制下的 IC₅₀为 9 nM）外。这些结果表明，在常规环境和食品监测计划中，用于检测有机磷和氨基甲酸酯的农药时，纯化和非纯化酶之间具有可比的敏感性，可将其作为生物标志物。
