乳酸片球菌产谷氨酸脱羧酶的相关酶学性质研究

摘要

This article researched on the property of glutamate decarboxylase,colorimetric method was used to measure the activity of GAD.The result showed that when the concentration of L-MSG was 100 mmol·L-1,GAD had the highest activity,the concentration of GAD was 3.16%,the optimal temperature was about 37℃,the optimal pH was 5,when the addition amount of PLP was 0.1mol·L-1,GAD had the highest activity.Mg2＋and Mn2＋ increased the enzyme activity by 10%,KCl,EDTA had decreased the enzyme activity,and KI,Ag2＋,SDS and CH3COOH could decrease more seriously.The michaelis constant of GAD was Km=0.365 8 mmol·L-1,Vmax was 3.03 μmol·L-1.%为研究乳酸片球菌谷氨酸脱羧酶（GAD）的性质,采用比色法测其酶活。结果表明：当底物L-MSG的浓度为100 mmol.L-1时,GAD的活力达到最大。GAD的浓度为3.16%,最适温度为37℃,最适pH为5.0,PLP浓度为0.1 mo.lL-1时,GAD酶活力最大。Mg2＋和Mn2＋使GAD活力提高10%左右,KCl和EDTA对GAD的活力稍有抑制,KI、Ag2＋、SDS和CH3COOH均对乳酸片球菌GAD的活力具有较大抑制。乳酸片球菌GAD的米氏常数Km=0.365 8 mmol.L-1,最大反应速度Vmax=3.03μmol.L-1。