尹洁; 朱军莉; 傅玲琳; 励建荣
浙江工商大学食品与生物工程学院; 浙江省食品安全重点实验室
【中文摘要】 通过(NH4)2SO4沉淀、Phenyl Sepharose FF疏水层析分离纯化香菇中的γ-谷氨酰转肽酶(γ-Glutamyltranspeptidase,GGT),纯化后的GGT的比活力到达了19.59U/mg。SDS-PAGE分析表明,GGT由分子量分别为28kDa和60kDa的两个亚基组成。酶学性质试验结果表明,GGT反应的最适温度为37℃,最适pH值为7.6;金属离子Na+、K+和Ca2+对酶有激活作用,而Ag+、Cu2+、Zn2+和Fe3+则有抑制作用;试验范围内,GGT水解γ-glutamyl-p-nitroanilide的米氏动力学参数Km值为2.601μmol/mL,Vmax值为0.0287μmol/min;组成的氨基酸中,Glu和Asp含量较高,Met和Cys含量较低。
【英文摘要】 γ-Glutamyltranspeptidase (GGT) was extracted from Lentinula edodes by ammonium sulfate precipitation and purified by Phenyl Sepharose FF column chromatography. The specificity activity of the purified GGT was 19.59 U/mg,and SDS-PAGE revealed that the enzyme consisted of two subunits of 28 kDa and 60 kDa,respectively. The optimal temperature and pH values for enzyme activity were 37 ℃ and 7.6,respectively. Na+,K+ and Ca2+ exerted a slight activating effect on GGT,whereas Cu2+,Ag+,Zn2+ and Fe3+ inhibited enzyme activity. The rate of γ-glutamyl-p-nitroanilide hydrolysis by purified GGT followed Michaelis-Menten kinetics over the substrate concentration range 50250 mmol/L (Km=2.601 μmol/mL,Vmax=0.0287 μmol/min). Purified GGT contained highest amounts of glutamic and aspartic acids,whereas Cys and Met were present in low amounts.
【中文关键词】 香菇; γ-谷氨酰转肽酶; 分离纯化; 酶学性质
【英文关键词】 Lentinula edodes; γ-glutamyltranspeptidase; enzyme purification; enzyme properties
【基金】教育部科学技术研究重点项目“香菇采后保鲜和加工过程中内生甲醛的形成和调控机理”(编号:208054)的部分研究内容~~
【文献出处】 食用菌学报,Acta Edulis Fungi,编辑部邮箱,2009年02期 【DOI】CNKI:SUN:SYJB.0.2009-02-010
