发芽粟谷中谷氨酸脱羧酶的主要酶学性质初探

摘要

[ Objective] The research aimed to discuss the main enzymatic properties of glutamate decarboxylase( GAD ) from germinated Setaria italica (L.) Beauv.. [ Method] With germinated Setaria italica (L.) Beanv. as research object, its GAD activity and some enzymatic properties of were studied. [ Result] The results showed that GAD from germinated Setaria italica (L.) Beauv. had an optimum temperature at 40 ℃, and its heat resistance was very weak, only exist 86.3% of its activity after keeping in 32 ℃ for an hour. The optimal pH value for germinated Setaria italica ( L. ) Bennv. was 5.5, GAD activity was stable when pH value was in the range of 5.0 -5.5, which could maintain 80.0% activity. K,m and Vmax values of germinated Setaria italica ( L. ) Beauv. GAD to glutamic acid were 22.36 mmol/L and 2. 28 μmol/min, respectively. Metal ions and chemical reagents such as Ca2+ , Mg2+ , Li+, PLP and VB6 increased the GAD activity, and Zn2+ , La3+ , Cu2 + decreased the enzyme activity, while Mn2+ , Na+, Fe2+ and EDTA had no effect on it. [ Conclusion ] The study can provide theoretical basis for utilizing GAD in germinated Setaria italica ( L. ) Beauv. to gathering Υ-aminobutyric acid (GABA).%[目的]探讨发芽粟谷[Setaria italica (L.)Beauv.]中谷氨酸脱羧酶(GAD)的主要酶学性质.[方法]以发芽粟谷为试材,研究发芽粟谷GAD的活性及其主要酶学性质.[结果]发芽粟谷GAD最适温度为40℃, 其耐热性较差,32℃保温1h后其酶活保持率为86.3%;发芽粟谷GAD最适pH值为5.5,在pH值5.0～5.5范围内酶活保持率在80.0%以上;发芽粟GAD对Glu的Km为22.36mmol/L,Vmax为2.28 μmol/min;Ca2+、Mg2+、Li+、PLP和VB6对发芽粟谷GAD活力具有促进作用,而Zn2+、La3+、Cu2+起抑制作用,Mn2+、Na+、Fe2+和EGTA则无显著影响.[结论]该研究可为利用发芽粟谷内源GAD富集GABA提供理论依据.