Santos Glauber Pereira Carvalho Dos, Assis Caio Rodrigo Dias de, Oliveira Vagne Melo, Cahu Thiago Barbosa, Silva Valdir Luna, Santos Juliana Ferreira, Yogui Gilvan Takeshi, Bezerra Ranilson Souza
Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica - DBIOq, Universidade Federal de Pernambuco, Recife, Brazil; Instituto de Tecnologia de Pernambuco - ITEP, Recife, Brazil.
Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica - DBIOq, Universidade Federal de Pernambuco, Recife, Brazil; Laboratório de Fisiologia Comparada e Comportamento Animal - LabFCCA, Departamento de Fisiologia e Farmacologia - DFF, Universidade Federal de Pernambuco, Recife, Brazil; Laboratório de Fisioecologia em Aquicultura - LAFAq and Laboratório de Sistemas de Produção Aquícola - LAPAq, Departamento Pesca e Aquicultura - DEPAq, Universidade Federal Rural de Pernambuco, Recife, Brazil; Laboratório de Compostos Orgânicos em Ecossistemas Costeiros e Marinhos - OrganoMAR, Departamento de Oceanografia - DOCEAN, Universidade Federal de Pernambuco, Recife, Brazil.
Comp Biochem Physiol C Toxicol Pharmacol. 2022 Feb;252:109225. doi: 10.1016/j.cbpc.2021.109225. Epub 2021 Oct 29.
Acetylcholinesterase (AChE; EC 3.1.1.7) from aquatic organisms have been used to evaluate the exposure of specimens to pesticides and heavy metals at sublethal levels in environmental samples. AChE of Mytella charruana was extracted to characterize its physicochemical and kinetic properties as well as the effect of organophosphate (dichlorvos, diazinon, chlorpyrifos, methyl-parathion and temephos), carbamates (carbaryl, carbofuran and aldicarb), benzoylureas (diflubenzuron and novaluron), pyrethroid (cypermethrin) and juvenile hormone analog - JHA (pyriproxyfen) and the effect of metal ions: Hg, Cd, Pb, As, Cu and Zn, in order to evaluate the potential of the enzyme as biomarker. The optimum pH of M. charruana AChE was 8.5 and the maximum activity peak occurred at 48 °C, being highly thermostable maintaining 97.8% of its activity after incubation at 60 °C. The Michaelis-Menten constants (k) for the substrates acetylthiocholine and propionylthiocholine were 2.8 ± 1.26 and 4.94 ± 6.9 mmol·L, respectively. The V values for the same substrates were 22.6 ± 0.90 and 10.2 ± 4.94 mU·mg, respectively. Specific inhibition results suggest an AChE presenting active site with dimensions between those of AChE and butyrylcholinesterase (BChE). The IC values related to the effect of the pesticides on the enzyme showed higher inhibitory power of temephos (0.17 μmol·L), followed by aldicarb (0.19 μmol·L) and diflubenzuron (0.23 μmol·L). Metal ions inhibited M. charruana enzyme in the following order: Hg > Pb > Cd > As > Cu > Zn. These data suggest that the enzyme showed potential as in vitro biomarker of the exposure to temephos, mercury, zinc and copper.
水生生物的乙酰胆碱酯酶（AChE；EC 3.1.1.7）已被用于评估环境样品中生物标本在亚致死水平下对农药和重金属的暴露情况。提取了查氏肌蛤的AChE，以表征其物理化学和动力学特性，以及有机磷（敌敌畏、二嗪农、毒死蜱、甲基对硫磷和双硫磷）、氨基甲酸酯（西维因、克百威和涕灭威）、苯甲酰脲（除虫脲和虱螨脲）、拟除虫菊酯（氯氰菊酯）和保幼激素类似物-JHA（吡丙醚）的影响，以及金属离子Hg、Cd、Pb、As、Cu和Zn的影响，以评估该酶作为生物标志物的潜力。查氏肌蛤AChE的最适pH为8.5，最大活性峰出现在48℃，具有高度的热稳定性，在60℃孵育后仍保持其活性的97.8%。底物乙酰硫代胆碱和丙酰硫代胆碱的米氏常数（k）分别为2.8±1.26和4.94±6.9 mmol·L。相同底物的V值分别为22.6±0.90和10.2±4.94 mU·mg。特异性抑制结果表明，AChE的活性位点尺寸介于AChE和丁酰胆碱酯酶（BChE）之间。与农药对该酶的影响相关的IC值显示，双硫磷（0.17 μmol·L）的抑制能力最强，其次是涕灭威（0.19 μmol·L）和除虫脲（0.23 μmol·L）。金属离子对查氏肌蛤酶的抑制顺序为：Hg＞Pb＞Cd＞As＞Cu＞Zn。这些数据表明，该酶显示出作为敌敌畏、汞、锌和铜暴露的体外生物标志物的潜力。
