【摘要】 目的 :用相对分子质量为 2 0 0 0～ 2 0 0 0 0的聚乙二醇 (PEG)修饰超氧化物歧化酶 (SOD) ,观察修饰后SOD的酶活力的变化及其对温度、pH和蛋白酶作用的稳定性。研究聚乙二醇修饰的超氧化物歧化酶口服后在动物体内代谢状况。方法 :以TNBS法测定修饰率 ,SOD活性测定试剂盒测试活性 ,在 70℃水浴中加热 3h ,考察其热稳定性 ,运用放射性核素标记和凝胶电泳结合的方法 ,研究其在动物体内代谢。结果 :发现相对分子质量 60 0 0的PEG修饰后SOD的稳定性较好。灌胃 0～ 72h内收集尿粪并测其放射性 ,尿的平均累计标记物的排泄率为给药量的 (19.9± 3 .1) % ,粪的排泄率为 (61.6± 5.1) %。结论 :表明相对分子质量为60 0 0的PEG修饰效果最佳。同时与天然的SOD相比 ,PEG SOD衍生物在耐热、耐酸、耐碱以及抗酶解方面都有显著的提高。在动物体内能透过小肠粘膜进入到血液中 ,大部分在血浆中 ,少量存在红细胞中 ,代谢物主要通过粪便排泄。更多还原

【Abstract】 ABSTRACT:OBJECTIVE Superoxide dismutase was modified with polyethylene glycols (MW 2000～20000),deviatives of superoxide dismutase were studied on the stability (including stability to heat,acid,alkali and enzymolysis) and the metabolism in animals.METHODS The modified ratio of SOD was determined by TNBS.The activity and stability of PEG SOD were also detected. the method of radio nuclide label combined with gel electrophoresis was used.RESULTS According to the result of experiment we found SOD modified with polyethylene glycol of MW 6000 is better on stability. In 0～72 hours,( 19.9 ± 3.1)% of the PEG SOD(PEG6000) were excreted in urine and ( 61.6 ± 5.1)% of the PEG SOD(PEG 6000) were excreted in feces.CONCLUSIONS The stability of PEG SOD increased significantly in heat,acid,alkali and enzymolysis. The PEG SOD(PEG 6000) could be absorbed by small intestine. The majority of it entered into plasma and the minority of it entered into enrythrocyte. The metabolites of PEG SOD(PEG6000) were excreted in feces.更多还原