摘要
采用化学修饰法研究僧帽牡蛎碱性磷酸酶活性功能基团性质.酶经0.4mmol·L-1PCMB修饰30min后活力仍然保持不变,提示巯基与酶的活力无关;用二巯基苏糖醇(DTT)对酶进行修饰,当DTT浓度达到2.5mmol·L-1时,酶活力丧失98%,表明硫 硫键与酶活力有密切的关系;以N 溴代琥珀酰亚胺(NBS)修饰酶的色氨酸残基,酶的修饰失活呈一级反应,当NBS浓度达到0.65mmol·L-1时,酶活力丧失100%,并辅以紫外吸收光谱的变化分析,表明色氨酸残基是酶催化活力所必需的;醋酸酐、马来酸酐、甲醛等氨基试剂对酶的修饰作用显示氨基是酶的必需基团.
The alkaline phosphatase from Ostrea cucullate were selectively modified by DTT,PCMB,NBS,acetic anhydride,succinic anhydride and formaldehyde,after that the changes in their activities have been detected. The enzyme was modified by PCMB in the concentrate of 0.4 mmol·L^(-1) for 30 min, and the enzyme activity was not influenced, indicating that the -SH group is not essentical to the enzyme's faction. Modification of dithiothreitol (DTT) on the enzyme resulted in 98% inhibition of the enzyme activity in the concentration of 2.5 mmol·L^(-1) of DTT. The result shows that the disulfide bonds are essential to the enzyme activity.By chemical modification with N-bromosuccinimide,the enzyme can be totally inactivated,followed by the UV absorption spectrum change,suggesting that the residue of tryptophan is essential for the activity and may be at the active site of the enzyme.The results of the chemical modification of the enzyme by acetic anhydride, succinic anhydride and formaldehyde demonstrate that the amino group is one of the enzyme's functional groups. Studies of inactivation of the enzyme by chemical modification demonstrated that Ser,Lys and Trp residues are essential functional groups of the enzyme.Partial disulfide bonds are essential for the function of this enzyme.
出处
《厦门大学学报（自然科学版）》
CAS
CSCD
北大核心
2004年第5期702-705,共4页
Journal of Xiamen University：Natural Science
基金
教育部跨世纪人才计划
厦门大学细胞生物学与肿瘤细胞工程教育部重点实验室开放基金资助
