生姜蛋白酶的大分子结合修饰  

Chemical Modification of Zinger Protease

作　　者：刘恩岐[1] 张建萍[1] 贺菊萍[1] 刘全德[1] 高明侠[1] 

机构地区：[1]徐州工程学院江苏省食品生物加工工程技术研究中心,江苏徐州221008

出　　处：《食品科学》2010年第21期320-323,共4页Food Science

基　　金：江苏省高校自然科学研究计划项目(08KJD550001)

摘　　要：采用单甲氧基聚乙二醇(mPEG)和右旋糖苷对生姜蛋白酶进行大分子结合修饰。在酶液质量浓度为2.0mg/mL的硼酸缓冲液中,加入三聚氯氰活化的mPEG或高碘酸钠活化的右旋糖苷,于40℃修饰反应1h,对修饰剂与酶蛋白的质量比和pH值条件进行优化:mPEG与酶的质量比为17.5:1.0、pH9.0,mPEG修饰酶的修饰率为52.6%,相对酶活力(修饰酶活力/天然酶活力)为54.0%;右旋糖苷与酶的质量比为42:1、pH6.0,右旋糖苷修饰酶的修饰率为51.6%,其相对酶活力为原天然酶的3.3倍。两种修饰酶的热稳定性均比天然酶显著增强,且右旋糖苷修饰酶的热稳定性明显高于mPEG修饰酶。结果表明:右旋糖苷对生姜蛋白酶的修饰效果优于聚乙二醇,适用于酶蛋白的化学修饰与新型酶制剂的开发利用。Zinger protease was modified separately with monomethoxypolyethylene glycol （mPEG） and dextran to promote its activity and stability.Dextran and mPEG were activated by sodium periodate and by cyanuric chloride,respectively.The activated mPEG and dextran were solely added into sodium tetraborate buffer solution with 2.0 mg/mL zinger protease and then the mixed solutions were incubated at 40 ℃ for 1 h.The optimal mass ratio between modifying agent and zinger protease,and reaction pH were measured.When the ratio between mPEG and zinger protease was 17.5：1.0 and pH was 9.0,the modification rate of zinger protease modified with mPEG was 52.6% and the relative enzyme activity （activity of modified enzyme/activity of natural enzyme） was 54.0%.The modification rate of zinger protease modified with dextran was 51.6% and the relative enzyme activity was 3.3 at the conditions of dextran/zinger protease ratio of 42：1 and pH 6.The thermal stability of both modified enzymes was higher than that of natural enzymes;meanwhile,the thermal stability of zinger protease modified with dextran was higher than that of zinger protease modified with mPEG.Therefore,dextran has a better modification effect on zinger protease than mPEG.Dextran is more suitable for the chemical modification of proteases and the development and utilization of novel enzymes.

关 键 词：生姜蛋白酶 单甲氧基聚乙二醇 右旋糖苷 化学修饰 

分 类 号：TS253.9[轻工技术与工程—农产品加工及贮藏工程]