用单甲氧基聚乙二醇-丙醛(mPEG-ALD)、单甲氧基聚乙二醇-丁醛(mPEG-ButyrALD)和单甲氧基聚乙二醇-琥珀酰亚胺碳酸酯(mPEG-SC)对猪胰岛素进行化学修饰. 考察了反应时间、pH、物质的量比及分子量等因素对修饰效果的影响. 通过HPLC, MALDI-TOF-MS(基质辅助激光解吸时间飞行质谱), SDS-PAGE(十二烷基硫酸钠-聚丙烯酰胺凝胶电泳)和TNBS(三硝基苯磺酸钠法)等表征发现mPEG-ButyrALD具有更高的修饰选择性和修饰率. 圆二色光谱(CD)分析修饰产物的二级结构发现, 胰岛素经mPEG衍生物修饰后, 二级结构基本没有改变. 动物实验表明, mPEG-ButyrALD修饰胰岛素后半衰期延长, 因而可以延长降血糖作用时间, 改善胰岛素药效.

Pork insulin was modified by three kinds of mPEG derivatives (mPEG-ALD, mPEG-ButyrALD and mPEG-SC) with different active moieties. The effects of reaction time, pH, molar ratio and molecular weight on the modification rate and site-selectivity were investigated. The results showed that mPEG-ButyrALD-INS had higher site-selectivity and modification rate compared to the other two modifiers characterized by HPLC, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and trinitrobenzene sulfonic acid (TNBS). The secondary structure of the mPEG-ylated insulins was studied by circular Dichroism (CD). It is found that the secondary structure of insulin was changed hardly after mPEGylation. The in vivo experiment results showed that mPEG-ButyrALD-INS displayed longer half-life and extended action profiles.