作　　者： ; ;

机构地区： 中国科学院上海生命科学研究院生物化学研究所

出　　处： 《生物化学杂志》 1996年第2期243-245,共3页

摘　　要： 蚕豆β－半乳糖苷酶活性必需氨基酸残基分析龚笑海，孙册（中国科学院上海生物化学研究所，上海２０００３１）化学修饰作为一种研究酶活性基团的方法，对研究糖苷酶的催化机理有其独到的优点，并已有这方面的报道．从蚕豆纯化的β－半乳糖苷酶，分子量为７０ｋＤ，由两个... Modification of purified β-galactosidase from Vica faba by NBS-EDC-glycine methyl ester and NAI led to complete and partial loss of enzyme activity respectively. When one Trp residue was modified, the activity of β-galactosidase dropped to zero. indicating that Trp residue was essential for enzyme activiry. The partial loss of β-galactosidase activity was caused by EDCglycine methyl ester treatment indicating that the carboxyl group was also essential for enzyme activity. D-galactose which is the competitive inhibitor of β-galactosidase could prevent the modification by EDC to a certain degree. but D-galactose showed no affect on modification by NBS. It is suggested that the carboxyl group may be related to the catalytic center of the enzyme and the Trp residue may not directly participate in the formation of the catalytic center. Modification of Arg ,His and Cys residues and free amino group of the enzyme molecule did not affect the activity,indicating that these residues are not necessary for the enzymic activity.

关 键 词： 蚕豆 半乳糖苷酶 酶活性 氨基酸残基

领　　域： [农业科学]