摘要
谷氨酸脱羧酶（ｇｌｕｔａｍａｔｅｄｅｃａｒｂｏｘｙｌａｓｅ，ＧＡＤ，ＥＣ４．１．１．１５）催化谷氨酸脱羧生成γ－氨基丁酸（γ－ａｍｉｎｏｂｕｔｙｒａｔｅ，ＢＡ），植物中已从南瓜［１］、马铃薯和林生山黧豆［２］纯化了ＧＡＤ．ＧＡＤ活性在禾本科作物中作为...
Glutamate Decarboxylase (GAD) was purified from wheat seedling in order to study its function during germination on stress.The purification steps included PEG6000 fractionation,DEAE Sepharose CL 6B,Sephadex G 200 and Lys Sepharose 4B chromatography.Its final specific activity was 29 U/mg protein at pH 5 8 with 138 purification folds and 10% yields.The wheat GAS had a M r of approximately 310 kD using Sephadex G 200 gel filtration.It was a hexamer with a subunit molecular weight of 50 kD as shown by SDS PAGE.The K m value for γ aminobutyrate was estimated to be 8.5 mmol/L.Determination of the p I and pH optimuim revealed 4.8 and 5.8 respectively.The enzyme was stable for a month at 4℃ in the dark at a concentration of 20 mmol/L PBS buffer including 0.4 mmol/L PLP and 0 1 mmol/L 2 mercaptoethanol and was heat stable up to 55℃.It showed strict specificity for the substrate.The GAD activity was inhibited by 2 mmol/L dithiothreitol and 0 1 mmol/L phenylethylsulfonyl fluoride(PMSF).
出处
《中国生物化学与分子生物学报》
CAS
CSCD
1998年第5期641-644,共4页
Chinese Journal of Biochemistry and Molecular Biology
关键词
谷氨酸脱羧酶
性质
纯化
Glutamate decarboxylase,Purification,Wheat
