甲醇与SDS对日本鳗鲡肠道蛋白酶催化活性的影响机理

Effects of methanol and SDS on catalytic activity of protease fromAnguillajaponica

【目的】探讨甲醇和十二烷基磺酸钠(SDS)对日本鳗鲡(Anguilla japonica)肠道蛋白酶催化活力的影响,揭示甲醇和SDS对蛋白酶催化活性的影响机理.【方法】利用酶促反应动力学方法,研究甲醇和SDS对蛋白酶催化活性的影响机理;通过对蛋白酶荧光发射光谱的测定,研究蛋白酶经甲醇和SDS溶剂微扰后的分子构象变化.【结果】甲醇和SDS对日本鳗鲡肠道蛋白酶均表现为失活作用,且失活作用都是可逆的;甲醇对蛋白酶的失活作用是属于非竞争性类型,而SDS的失活效应则表现为竞争性类型.蛋白酶经甲醇作用后荧光发射强度呈现减小现象,而经SDS作用后蛋白酶荧光发射强度呈增大现象,但荧光发射光谱的波长均没有发生变化.【结论】甲醇和SDS对日本鳗鲡肠道蛋白酶均具有失活作用,都是通过影响酶蛋白的空间构象而使酶失去催化活性的.

【Objective】To study the effects of methanol and sodium dodecyl sulfate（SDS）on intestine protease activity fromAnguilla japonica,to investigate the influence mechanism of methanol and SDS on the catalysis of protease.【Method】The influence mechanism of methanol and SDS on the catalysis of protease were studied by using the kinetics of enzymatic reaction.Conformational changes of the protease in different concentrations of methanol and SDS were determined through measuring their fluorescence spectra.【Result】Methanol and SDS led to the protease activity lost,the inactivation caused by methanol and SDS could be reversible.The kinetics showed that the inactivation of protease caused by methanol was noncompetitive type,and the inactivation of protease caused by SDS was competitive type.Fluorescence emission spectra showed that the fluorescence intensity of protease increased in SDS,and decreased in methanol.The fluorescence emission peak of protease had no shifted in different concentration of methanol and SDS.【Conclusion】Methanol and SDS lead to loss of the protease activity of A.japonica.The conformation changes caused by methanol and SDS lead to inactivation of protease.