摘要
研究了米糠谷氨酸脱羧酶(GAD)的酶学性质。结果表明:米糠GAD的最适温度为40℃,最适pH5.6,米糠GAD耐热性较差,60℃下保温0.5 h后,酶活下降至65%,保温1 h,酶活下降至48%,而70℃时酶就完全失活,而此酶在pH5.5～9都可以保持84%以上的酶活力。米糠GAD对底物和辅酶PLP的Km分别为0.028 45 mol/L和1.13μmol/L。KI、Ag^(2+)、SDS、乙酸对米糠GAD的活力有较大的抑制作用,而Ca^(2+)对米糠GAD的活性有较强的激活作用,提高了底物与米糠GAD的亲和力。
Some properties of glutamate decarboxylase （GAD） from rice bran were studied. The optimal temperature for rice bran GAD is 40℃ and optimal pH is 5.6. The enzyme lost almost all of its activity at 70℃, but it was stable over a pH range of 5.5-9. Km of Rice bran GAD to glutamic acid was 0. 02845 mol/L, and 1. 13μmol/L to PLP. KI, Ag^2＋ , SDS and acetic acid restrained the GAD activity to a great degree. Ca^2＋ showed a positive effect on the GAD activity as it lows down the Km of substrate.
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2008年第5期24-28,共5页
Food and Fermentation Industries
基金
国家自然科学基金(20671044)
“新世纪优秀人才支持计划”资助项目(NCET-06-0488)
关键词
米糠
谷氨酸脱羧酶
Γ-氨基丁酸
酶学性质
rice bran, glutamate decarboxylase, gamma a minobutyric, enzymatic properties
