【摘要】 巨尾阿丽蝇幼虫肠液ＳＤＳＰＡＧＥ后，Ｘ光片显影呈现３条蛋白酶活性带。ＩＥＦ后出现２条蛋白酶活性带，等电点分别为ｐＨ８５和ｐＨ７７。肠液经硫铵沉淀，ＳｅｐｈａｄｅｘＧ７５凝胶过滤，ＳｅｐｈａｄｅｘＤＥＡＥＡ２５离子交换和ＳＢＢＩＳｅｐｈａｒｏｓｅ４Ｂ亲和层析，分离纯化出分子量约为１４ｋＤ的巨尾阿丽蝇蛋白酶。专一底物和抑制剂的测定结果表明，巨尾阿丽蝇蛋白酶为类胰蛋白酶，能分解类胰蛋白酶专一底物，而不能分解类胰凝乳蛋白酶和弹性蛋白酶专一底物。ＰＭＳＦ，ＳＢＢＩ，Ｌｅｕｐｅｐｔｉｎ和Ａｎｔｉｐａｉｎ能抑制巨尾阿丽蝇蛋白酶活性。该蛋白酶最适反应温度为５０℃，最适作用ｐＨ为９０。Ｐｂ２＋、Ｚｎ２＋和Ｈｇ２＋能抑制其活性。Ｍｇ２＋和Ｃａ２＋对巨尾阿丽蝇蛋白酶活性无激活作用，ＥＤＴＡ无抑制作用。更多还原

【Abstract】 The gut proteolytic activity of Aldrichina grahami larva was detected. Separation of gut enzyme extract by SDS PAGE and subsequent incubation with X ray film visualized three separate bands of protease activity. Separation by IEF showed two separate bands of protease activity with isoelectric point pH 8 5 and pH 7 7 respectively. A trypsin like enzyme(AGP, Mr 14kD) was purified after ammonium sulfate precipitation, Sephadex G 75 gel filtration, Sephadex DEAE A 25 ion exchange chromatography and SBBI Sepharose 4B affinity chromatography. AGP showed strong activity against casein and Bz Phe Val Arg NA(specific substrate for trypsin), but no activity against elastin Congo Red (specific substrate for elastase) and Suc(Ala) 2Pro Phe NA (specific substrate for chymotrypsin). It was strongly inhibited by PMSF, SBBI, Leupeptin and Antipain. Pb 2+ , Zn 2+ and Hg 2+ inactivated AGP, but Ca 2+ and Mg 2+ did not increase its activity. It was most active at pH 9 0 and 50℃.更多还原