中文摘要：

目的：通过高碘酸钠氧化法以麦芽糖修饰胰蛋白酶,检验此方法是否能够改善胰蛋白酶的稳定性。方法：采用高碘酸钠改性麦芽糖,使其中具有能够与酶分子中氨基结合的醛基,从而在一定条件下化学修饰胰蛋白酶。结果：改性麦芽糖的最佳条件为,高碘酸钠浓度0.05g/mL,高碘酸钠与麦芽糖质量比1.1∶1,初始pH1.0,反应时间3h,反应温度30℃;修饰胰蛋白酶的最佳条件为,pH6.0,改性麦芽糖与胰蛋白酶质量比1∶1,修饰温度4℃,修饰时间24h;在最佳条件下修饰酶后,pH在8.9～10.0时,原酶活力与修饰酶活力分别下降了其最高活力的15.8%和9.8%;将酶置于50℃2h后,原酶与修饰酶分别保留了其置于4℃2h后活力的88.7%和94.7%。结论：该方法能够提高胰蛋白酶的耐碱稳定性和热稳定性。

英文摘要：

Objective：Trypsin was modified with maltose by oxidation method with sodium periodate.Whether this method could improve the stability of trypsin was checked.Method：Maltose was modified with sodium periodate,in order that there was aldehyde group which could combine with amino-group of enzyme molecule in it,so it could modify trypsin chemically under certain conditions.Result：The optimum conditions for modifying maltose were as follows：Concentration of sodium periodate 0.05g/mL,Mass ratio of sodium periodate and maltose 1.1∶1,Initial pH 1.0,Reaction time 3h,Reaction temperature 30℃;The optimum conditions for modifying trypsin were as follows：pH 6.0,Mass ratio of modified maltose and trypsin 1∶1,Modification temperature 4℃,Modification time 24h;After trypsin was modified under the optimum conditions,the activity of the original trypsin and the modified trypsin dropped 15.8% and 9.8% of their highest activity respectively within pH8.9-10.0;Under 50℃ for 2h,the activity of the original trypsin and the modified trypsin retained 88.7% and 94.7% of their activity under 4℃ for 2h respectively.Conclusion：This method could improve stability for resisting alkali and heat of trypsin.