聚乙二醇修饰尿酸酶的研究(英文)

Research on PEG modification of uricase

目的:为了降低尿酸酶的免疫原性并提高其稳定性,利用PEG修饰剂对尿酸酶进行修饰,以期获得性质更优的治疗痛风的药物。方法:用相对分子质量为40kD,活化基团为羟基琥珀酰亚胺的PEG修饰剂对尿酸酶进行修饰,并比较修饰前后在酶解稳定性、pH稳定性及温度稳定性方面的差异,以及PEG修饰对体内半衰期,免疫原性的影响。结果:发现PEG修饰后尿酸酶的酶解稳定性显著提高,PEG化尿酸酶保留了原有尿酸酶80%的活性,体内半衰期从45min延长至696min。PEG化尿酸酶与抗体的结合能力为原型蛋白的1/8。体内的免疫原性也明显降低。结论:化学修饰后的尿酸酶可望成为潜在的治疗痛风的有效药物。

Aim： To modify uricase with PEG reagent in order to decrease uricase immunogenicity and increase its stability. Methods： The branched PEG of 40 kD was chosen to modify native uricase. The properties of the modified uricase including the stabilities to protease, pH and temperature, in vivo half-life time, as well as the immunogenicity were evaluated. The pharmacokinetie profiles of the midofied uriease were studied in mice. Results： It is demonstrated that the conjugation of PEG to lysine residues of Candida utilis uricase resulted in higher trypsin resistance, reduced immune response, and prolonged in vivo half-life. PEG modified uricase retained 80% of the enzymatic activity of native uricase. In addition, it was found that half-life in serum of the intravenously injected PEGylated uricase of up to 696 rain was longer that that of native uricase of 45 min. Higher plasma drug concentrations were also reached with dosing of the PEGylated uricase to mice. Furthermore, the binding affinity was shown to be reduced for the PEG-uricase using ELISA assay, and it was one-eighth that of native uricase. Finally, it was indicated that the PEG uricase induced a delayed immunoresponse in mice following repeated administrations. Conclusion： These findings demonstrate that this chemically modified form of uricase may serve as a potentially effective drug to treat gout patients.