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为研究棉铃虫酯酶对有机磷和拟除虫菊酯类杀虫剂的代谢活性,在前期对酯酶001F和001G酶活性研究的基础上,进一步采用荧光法和高效液相色谱法测定了酯酶及其突变体(A127位和F238位突变)对二甲基-4甲基伞形酮磷酸酯(dMUP)、二乙基-7羟基香豆素磷酸酯(dECP)及顺式氰戊菊酯(2S,αS)的酶促代谢活性。酯酶001F和001G对有机磷的酶促反应常数(kcat值)在2.0×10-3/min～5.2×10-3/min之间,后者对顺式氰戊菊酯的代谢活性为10.19μmol.min-1.μmol-1;001F的突变提高了对有机磷的代谢活性,其中001FA127D和001FF238L对dMUP的kcat值至少是突变前的2倍;001G的突变却降低了对dECP的代谢活性,但001GF238L对dMUP的活性有所提高。此外,突变体中001FA127D对顺式氰戊菊酯的活性与突变前接近,而001GF238L则降低到突变前的1/2,其它突变体未检测到活性。结果表明,酯酶001F和001G对杀虫剂有代谢活性,A127位和F238位的突变对酶活性有显著影响。
In order to study the metabolic activity of the esterase of Helicoverpa armigera to organophosphorus and pyrethroid insecticides, based on the previous studies on the enzyme activities of the esterase 001F and 001G, the esterase was further detected by fluorescence and high performance liquid chromatography (DMUP), diethyl-7-hydroxycoumarin phosphate (dECP) and cis-esfenvalerate (mutant A127 and F238) (2S, αS) enzymatic metabolic activity. The enzymatic reaction constants (kcat values) of the esterases 001F and 001G to the organophosphorus ranged from 2.0 × 10-3 / min to 5.2 × 10-3 / min, and the metabolic activity of the latter to cis-fenvalerate was 10.19 The mutation of 001F increased the metabolic activity of organophosphorus. The kcat values of 001FA127D and 001FF238L for dMUP were at least two-fold higher than that of dMUP. The mutation of 001G reduced the metabolic activity of dECP , But 001GF238L increased the activity of dMUP. In addition, 001FA127D had similar activity to cis-fenvalerate in the mutants, but 001GF238L decreased to 1/2 before mutation. No activity was detected in other mutants. The results showed that esterase 001F and 001G had metabolic activity on insecticides, and mutations at positions A127 and F238 had a significant effect on the enzyme activity.