氯氰菊酯的酶促降解研究

Study on enzymatic degradation of cypermethrin

从氯氰菊酯高效降解真菌镰孢霉属(Fusarium)菌株TS-203中提取了降解酶,研究了降解酶对氯氰菊酯的降解特性。结果表明,胞内酶对氯氰菊酯的降解率高达59.8%,细胞碎片对氯氰菊酯的降解率为47.6%,而由(NH4)2SO4沉淀法提取到的胞外酶对氯氰菊酯的降解率仅为10.3%,由此确定菌株TS-203产生的降解酶为胞内酶。以牛血清白蛋白为标准蛋白测得胞内粗酶液中可溶性蛋白质含量为3.24 mg/mL;该酶对氯氰菊酯酶促降解的最适pH为7.0,最适温度为30℃,降解酶的米氏常数Km为6.8120×10-4 mmol/mL,最大反应速度Vmax为1.1799×10-4 mmol/min。研究结果表明,该酶具有较好的热稳定性和pH稳定性,对热和pH均具有较好的耐受力,对氯氰菊酯降解效果较好。

Degradation characteristics of cypermethrin were studied by the degrading enzyme extracted from the efficiently cypermethrin-degrading fungal strain TS-203 （Fusarium）. The results showed that the degradation rates of cypermethrin by the intracellular enzyme, cell fragment and the extracellular enzyme which was extracted with （NH4 ）2SO4 were 59.8% , 47.6% and 10. 3% ,respectively. So the degrading enzyme produced by the fun- gal strain TS-203 was identified as intracellular enzyme. The solubility protein of the crude intracellular enzyme was determined with bovine serum albumin as standard protein and the solubility protein of the crude intracellular enzyme was 3.24 mg/mL. The crude intracellular enzyme had optimum pH 7.0 and temperature 30 ℃ for enzy- matic degradation of cypermethrin. The Michaelis-mentn＇ s constant of the degrading enzyme was 6. 8120 × 10^-4 mmol/mL and the Vmax for the degradation of cypermethrin was 1. 1799 × 10 ^-4 mmol/min. Additional experimen- tal evidence suggests that the enzyme had good stability and endurance for temperature and pH,the enzyme could efectively degrade cypermethrin.