斑点叉尾鮰鱼肠蛋白酶的分离纯化及其酶学性质

摘要

以斑点叉尾鲴Ictalurus punctatus鱼肠道为原料提取蛋白酶,对分离条件进行了优化,并对部分酶学性质进行了研究.结果表明:鱼肠内的蛋白酶在硫酸铵饱和度为70％时,所得沉淀中酶活力最高.经过阴离子交换层析分离后,蛋白酶的纯化倍数达到了218倍.该蛋白酶的最适温度为55℃,最适pH为7.5,具有良好的低温稳定性和酸碱稳定性,米氏常数为5.4 g/L.K+和Ca2+离子对该蛋白酶活性有较弱的激活作用,Mg2+则能显著激活蛋白酶活性；Na+和Zn2+对蛋白酶的活性有较弱抑制作用,而Cu2+和EDTA能显著抑制蛋白酶活性.%The paper studies purification and characterization of protease from intestines of Ictalurus punctatus. The result demonstrates that protease has the maximum activity with 70% saturation (NH4)2SO4 in crude extraction so lution. By using ion exchange chromatography, protease is purified 218-fold. It further shows that the optimal tem perature and pH is 55℃ and 7. 5 respectively for protease with optimal stability,and that Michaelis constant is 5.4 g/L. K+ ,Mg2+and Ca2+ may enhance protease activity. Na+ ,Zn2+ ,Cu2+ and EDTA may reduce protease activity.