鲫鱼乙酰胆碱酯酶性质及对有机磷农药的敏感性研究

Study on Property and Sensitivity to Organophosphorus Pesticides of Crucian AChE

以鲫鱼为原料,分别提取鱼脑、肌肉和肝脏乙酰胆碱酯酶(acetylcholinesterase,ACh E),研究其酶学性质及对有机磷农药的敏感性。结果表明,鲫鱼脑ACh E最适反应温度为30℃,最适p H为8.0,米氏常数(Michaelis constant,Km)为0.548 mmol/L;鲫鱼肌肉ACh E最适反应温度为35℃,最适p H为7.5,Km为1.75 mmol/L;鲫鱼肝脏ACh E最适反应温度为30℃,最适p H为8.0,Km为0.406 mmol/L。敌敌畏对鱼脑、肌肉和肝脏ACh E的半数抑制质量浓度(50%inhibition concentration,IC50)分别为1.70,3.55和4.52μg/m L,双分子速率常数(bimolecular rate constant,Ki)分别为7.40、7.21、5.94 L/mg·min;辛硫磷对鱼脑、肌肉和肝脏ACh E的IC50分别为2.45,4.05和9.46μg/m L,Ki分别为10.54,10.11和8.32 L/mg·min;毒死蜱对鱼脑、肌肉和肝脏ACh E的IC50分别为10.89、14.33和17.00μg/m L,Ki分别为7.81,6.85和4.99 L/mg·min。鲫鱼脑ACh E对常用有机磷农药表现出了较强的敏感性,可作为环境中有机磷农药残留监测的指示酶。

The acetylcholinesterase （ACHE） was extracted from brain, muscle and liver from crucian, and its enzyme property and the sensitivity to organophosphorus pesticides （OPs） were studied. The results indicated that the crucian brain ACHE＇ most optimum condition was that temperature of 30 ℃, pH of 8.0, Michaelis constant （Kin） of 0.548 mmol/L; crucian muscle ACHE＇ most optimum condition was that temperature of 35 ℃, pH of 7.5, Kj of 1.75 retool/L; crucian liver ACHE＇ most optimum condition was that temperature of 30℃, pH of 8.0, Ki of 0.406 mmol/L. The 50% inhibition concentration （IC50） of dichlorvos to crucian brain, muscle and liver ACHE was 1.70, 3.55 and 4.52 μg/mL, respectively; The bimolecular rate constant （Kj） to crucian brain, muscle and liver ACHE was 7.40, 7.21 and 5.94 L/mg.min, respectively; The IC50 ofphoxim to cmcian brain, muscle and liver ACHE was 2.45, 4.05 and 9.46/ag/mL, respectively; The Ki to cmcian brain, muscle and liver AChE was 10.54, 10.11 and 8.32 L/mg.min, respectively; the IC50 ofphoxim to crucian brain, muscle and liver AChE was 10.89 and 14.33 and 17.00 μg/mL, respectively; The Ki to crucian brain, muscle and liver AChE was 7.81, 6.85 and 4.99 L/mg.min, respectively. The crucian brain AChE was showed high sensitivity to common OPs, so it could be used as indicative enzyme to monitor the OPs＇ residual level in the environment.