米糠谷氨酸脱羧酶的分离纯化及酶学性质研究  

Purification and characterization of glutamate decarboxylase from rice bran

作　　者：徐冬霞[1] 王立[1] 吕莹果[1] 姜启兴[1] 张晖[1] 

机构地区：[1]江南大学食品学院,食品科学与工程国家重点实验室,江苏无锡214122

出　　处：《食品工业科技》2009年第12期193-196,296,共5页Science and Technology of Food Industry

基　　金：国家自然科学基金项目(20671044);江南大学食品学院青年博士科研创新开放基金资助(FS-200810)

摘　　要：利用(NH4)2SO4分级沉淀、DEAE-Sephrose FF离子交换色谱技术分离纯化米糠谷氨酸脱羧酶(GAD)。米糠GAD纯化倍数为8·8,比活达到了30·1U/mg,酶活回收率为45·5%。同时对米糠GAD酶学性质进行了研究,结果表明,最适温度为40℃,耐热性较差;最适pH5·5,在pH5·5～9都可以保持较高酶活。米糠GAD对底物和辅酶PLP的Km分别为28·45、1·13μmol/L。KI、Ag+、SDS、乙酸对米糠GAD的活力有较大的抑制作用,而Ca2+对米糠GAD的活性有较强的激活作用。Glutamate decarboxylase （GAD） was purified by using （ NH4 ） 2 SO4 fractionation and DEAE- Sephrose FF ion exchange chromatography.GAD was purified 8.8-folds.The specific activity was 30.1 U/mg,and the enzymatic activity recovery was 45.5%.The optimum temperature of GAD was 40℃, and it was inactive at 70℃.The optimum pH was 5.5 ,and it was stable at pH5.5-9.0.Km values for GAD and PLP were determined at 28.45 and 1.13μmol/L, respectively.Chemicals reagent s such as KI,Ag ＋ ,SDS and acetic acid decreased the enzyme activity, but Ca2＋ increased the GAD activity greatly.

关 键 词：米糠 谷氨酸脱羧酶 Γ-氨基丁酸 纯化 酶学性质 

分 类 号：TS201.2[轻工技术与工程—食品科学]