重组人粒细胞集落刺激因子的N端氨基定点PEG化修饰

尽管重组粒细胞集落刺激因子(rhG-CSF)具有重大的治疗价值，然而在实际应用却受到体内半衰期过短因而需要频繁重复注射的限制．为了解决这一问题，我们利用两种不同分子量（5 kD和 20 kD）的单甲氧基聚乙二醇丙醛（mPEG-PAL）对rhG-CSF的N端氨基进行了定点PEG化修饰．通过正交实验的统计学方法得到了最适修饰条件．研究发现，PEG化后的rhG-CSF具有了更高的体外稳定性，其体内活性也得到了很大提高，体内作用时间得到很大延长．因此，对于rhG-CSF的N端氨基定点PEG化修饰，可以显著提高rhG-CSF的临床应用价值．

N-Terminal Site-specific Mono-PEGylation of Recombinant Human Granulocyte Colony Stimulating Factor

Despite of all its therapeutic values for human beings, the use of recombinant human granulocyte colony-stimulating factor (rhG-CSF) has a primary limitation because of its short half-life in the peripheral blood. In order to solve this problem, the N-terminus of rhG-CSF was PEGylated in a site-specific manner by methoxy poly-ethylene glycol (mPEG) propionaldehydes with an average molecular weight of either 5 kD or 20 kD, respectively. With a statistical L9 (34) orthogonal test, the optimal conditions of the site-specific reaction were achieved. The results indicated that PEG-rhG-CSF had higher stability than unmodified rhG-CSF while incubated with protease or human serum or placed in an extreme environment such as at an extreme temperature or in a solution with extreme pH. Meanwhile the modified rhG-CSF increased the number of leukocytes in the blood of Kunming mice much more significantly than did unmodified rhG-CSF. In conclusion, these results show that PEGylation not only enhances the stability of rhG-CSF in vitro,but also distinctly increases its in vivo activity and thus this PEGylation promotes the clinical application of rhGCSF.