右旋糖苷对生姜蛋白酶的化学修饰及其酶学性质影响  

Zingibain: Chemical Modification Using Dextran and Enzymatic Properties

作　　者：张建萍[1] 刘恩岐[1] 巫永华[1] 陈尚龙[1] 

机构地区：[1]徐州工程学院江苏省食品资源开发与质量安全重点建设实验室,江苏徐州221008

出　　处：《食品科学》2013年第9期228-233,共6页Food Science

基　　金：江苏省高校自然科学研究计划项目(08KJD550001)

摘　　要：以NaIO4活化的右旋糖苷为修饰剂,研究修饰反应条件对生姜蛋白酶化学修饰效果的影响与修饰前后酶学性质及构型构象的变化。结果表明:较佳修饰条件为温度42℃、pH6.0、酶与活化右旋糖苷质量比1:22、修饰时间3h。与修饰前天然生姜蛋白酶相比,修饰酶的相对酶活力提高了2.0倍,酶蛋白氨基修饰率为57.8%。以酪蛋白为底物时,修饰酶的最适温度、最适pH值和酶反应动力学参数Km值较天然生姜蛋白酶均有所降低,热稳定性明显增强;修饰酶的紫外光谱吸收峰向长波长方向偏移,构型构象发生了变化。Dextran was activated by sodium periodate for use as a modifying reagent in the chemical modification of zingibain.In order to find an optimum method for chemcial modification,the effects of different modification conditions were studied by orthogonal array design.Some enzymatic properties of natural and modified zingibain were investigated,and their structures were investigated by ultraviolet absorption spectroscopy.The results showed that the modification rate of zingibain using activated dextran was 57.8% and the relative enzyme activity was 2.0 times higher than that of the natural enzyme under the conditions： the ratio of zingibain： activated dextran = 1：22（m/m） and pH 6.0 at 42 ℃ for 3 h.Compared with the natural enzyme,the optimal reaction temperature and pH and the Kmof the modified enzyme using casein as the substrate were reduced,and the thermostability of the modified enzyme was increased significantly.The spectral analysis showed that the configuration and conformation of the modified enzyme were quite different from those of the natural enzyme.

关 键 词：右旋糖苷 生姜蛋白酶 化学修饰 酶学性质 

分 类 号：TS253.9[轻工技术与工程—农产品加工及贮藏工程]