抑制剂和激活剂对梨星毛虫中肠蛋白酶活性的影响

Effects of Inhibitors and Activators on Protease Activity in the Midgut of Illiberis pruni

旨在研究不同抑制剂和激活剂对梨星毛虫Illiberis pruni中肠蛋白酶活性的影响。利用生化技术分别测定梨星毛虫幼虫不同龄期的4种中肠蛋白酶(总蛋白酶、强碱性胰蛋白酶、弱碱性胰蛋白酶和胰凝乳蛋白酶)活性,进而在最适龄期(4龄幼虫)测定蛋白酶激活剂(EDTA,MgCl_(2),EGTA,CaCl_(2))和抑制剂(PMSF,TPCK,STI,TLCK,IAA,DTT)对梨星毛虫中肠蛋白酶活性的影响。结果表明:梨星毛虫幼虫中肠总蛋白酶、强碱性胰蛋白酶、弱碱性胰蛋白酶、胰凝乳蛋白酶均在4龄具有最高酶活性。所有试剂均对总蛋白酶有激活作用;5mmol/LCaCl_(2)对强碱性胰蛋白酶抑制作用最高;对弱碱性胰蛋白酶有抑制作用的仅有5mmol/L DTT;对胰凝乳蛋白酶抑制效果最佳的为10mmol/LEGTA。所筛选的对梨星毛虫主要中肠蛋白酶具有抑制作用的抑制剂,对以昆虫中肠蛋白酶为靶标的绿色害虫防控技术的开发具有参考价值。

This paper aims to investigate the effects of different inhibitors and activators on the midgutprotease activity of the Illiberis pruni.Determination of the activities of four midgut proteases(totalprotease,high-alkaline trypsin,low-alkaline trypsin and chymotrypsin)in different instar larvae ofIlliberis pruni by biochemical techniques,and then the effects of protease activators(EDTA,MgCl_(2),EGTA,MgCl_(2))and inhibitors(PMSF,TPCK,STI,TLCK,IAA,DTT)on the midgut protease activity of Illiberis pruni were determined at the optimum age(4th instar larvae).The results showedthat total protease,high-alkaline trypsin,low-alkaline trypsin and chymotrypsin have the highest enzymatic activities at the 4th instar.Under the optimum conditions,all reagents have activating effectson total protease;5 mmol/L CaCl_(2),have the highest inhibitory effect on high-alkaline trypsin;only 5mmol/L DTT have inhibitory effect on low-alkaline trypsin;10 mmol/L EGTA have the best inhibitory effect on chymotrypsin.The screened inhibitor has inhibitory effect on the main midgut proteasesof Illiberis pruni,which has reference value for the development of green pest control technology targeting insect midgut proteases.