鸡脑乙酰胆碱酯酶的性质及对氨基甲酸酯类物质的敏感性研究

Study on carbamate sensitivity of acetycholinesterase extracted from chicken brain

利用双水相萃取鸡脑中的乙酰胆碱酯酶(acetycholinesterase,ACh E),研究其酶学性质发现:鸡脑ACh E最适反应温度为37℃,最适反应p H为7.5,米氏常数Km为5.67×10^(-5)mol·L^(-1),最大反应速率Vm为0.20×10~2mol·(min·L)^(-1)。鸡脑ACh E的Km值明显小于商品ACh E的Km值,表明鸡脑ACh E对底物具有更大的亲和力。研究ACh E对氨基甲酸酯类物质的敏感性发现:该酶对5种氨基甲酸酯类有毒成分呋喃丹、灭多威、西维因、涕灭威、速灭威的半抑制浓度分别为0.004、0.07、0.23、0.53、5.24μg·m L^(-1);其双分子速率常数分别为40.89×10~5、3.09×10~5、2.80×10~5、2.78×10~5、2.74×10~5L·(mol·min)^(-1)。鸡脑ACh E对氨基甲酸酯类有毒成分表现出较强的敏感性,具有低成本、高活性、制备简单的优点,对氨基甲酸酯类有毒成分残留的检测具有重要意义。

Acetycholinesterase（ ACh E） was extracted from chicken brain by aqueous two- phase,and its enzymatic characteristics was studied.The result showed that the most optimum conditions of chicken brain ACh E were 37 ℃and p H7.5,Km5.67 × 10^-5mol·L^-1,Vm0.20 × 10^-2mol·（ min·L）^-1,indicating its more affinity to the substrate,compared with commercial ACh E. Its sensitivity to carbamate was studied. The result indicated that the 50%inhibition concentration of five carbamate toxins（ carbofuran methomyl,carbaryl,aldicarb,metolcarb） were 0.004,0.07,0.23,0.53,5.24 μg·m L^-1,and the bimolecular rate constants were 40.89 × 10^-5,3.09 × 10^-5,2.80 × 10^-5,2.78 × 10^-5,2.74 × 10^-5L·（ mol·min）^-1.These results proved that the ACh E extracted from chicken brain was more sensitive to carbamate toxins and had the advantages of low cost,high activity and simple preparation. The ACh E extracted from chicken brain showed its great siginificance in carbamate toxins residue detection.