中文摘要：

制备氨基末端定点PEG修饰的尿酸酶，并比较尿酸酶修饰前后的免疫原性差异。采用M20k的mPEG-丙醛选择性修饰尿酸酶的氨基末端；利用source 30Q离子交换层析和sephacryl S-200分子排阻层析分离纯化修饰后尿酸酶；测定修饰前后尿酸酶的酶动力学参数和免疫原性。尿酸酶和N端PEG修饰尿酸酶的SDS—PAGE检测显示单一条带，SE—HPIC测定尿酸酶修饰前后的保留时间分别为26．578min和23．818min；PEG修饰后尿酸酶的最大反应速度为尿酸酶的80％；PEG修饰后尿酸酶与抗体的结合能力和体内的免疫原性均明显降低。这种方法可用来制备N端PEG定点修饰尿酸酶，修饰后可明显降低尿酸酶的免疫原性。

英文摘要：

To prepare the N-terminal site-specific PEGylated uricase and to study the immunogenicity in vivo, the uricase reacted with monomethoxyl polyethylene glycol propionaldehyde （20 ku）. The PEGylated uricase was purified by source 30Q ion-exchange and sephacryl S- 200 size-exclusion chromatography, and the enzyme kinetics and immunogenicity were then investigated. SDS- PAGE demonstrated that the PEGylated uricase and uricase showed a single band. Retention time of PEGylated uricase detected by SE- HPLC was 23.818 min and uricase was 26.578 min. PEG modified uricase retained 80 % of the enzymatic V of native uricase. In addition, the binding affinity was shown to be reduced for the PEG-uricase using ELISA assay. Finally, it was indicated that the PEG uricase induced a delayed immunoresponse in mice following repeated administrations. The N-terminal site-specific PEGylated uricase can be prepared by this method. PEGylated can decrease the immunogenicity of uriease.