摘要
应用化学修饰法研究福寿螺β－葡萄糖苷酶活性功能基团的性质．用５，５′－二硫代双（２－硝基苯甲酸）和对－氯汞苯甲酸为修饰剂修饰酶分子中的巯基，酶活力基本不受影响，说明该酶不是“巯基酶”．用Ｎ－溴代琥珀酰亚胺在ｐＨ６．０下修饰酶后，可使酶活力完全丧失，被修饰后的酶分子在２７８ｎｍ处的紫外吸收峰逐渐下降至完全消失，３３８ｎｍ处的荧光发射峰也逐渐下降至完全淬灭，说明色氨酸残基是酶活性必需基团之一．用碳二亚胺、溴代乙酸或甲醛修饰酶，可以使酶活力完全丧失，说明羧基、组氨酸的咪唑基及赖氨酸的氨基也与酶活性有密切的关系．用乙酰丙酮、苯甲磺酰氟修饰酶，酶活力不受影响，表明精氨酸残基和羟基与酶活性无关．
The chemical modification of p chloromercuric benzoic acid and 5,5′ dithiobis (2 nitrobenzoic acid) on the β Glucosidase from Ampullarium Crossean demonstrates that the sulfhydryl group is not essential for the activity of the enzyme, indicating that the enzyme is not a sulfhydryl enzyme. The enzyme modified with N bromosuccinimide is totally inactivated and its characteristic peak of UV absorption spectrum at 278 nm also destroyed, and the 338 nm peak of the fluorescence emission spectrum is gradually descended and eventually lost, indicating that the tryplophan residues are essential to the enzyme′s function. The results of modification of carboxyl group by carbodiimide hydrochlorid, imidazole group by bromoacetic acid, and amino group by formaldehyde are essential for the enzyme′s activity, too. The modification of arginine residue by acetyl acetone and serine residue by phenylmethanesulfonyl fluoride showed that the arginine and serine residues were not essential to the enzyme′s function.
出处
《厦门大学学报（自然科学版）》
CAS
CSCD
北大核心
1999年第2期292-296,共5页
Journal of Xiamen University：Natural Science
基金
福建省自然科学基金
