聚乙二醇修饰重组人粒细胞集落刺激因子反应过程的优化

Process Optimization in Modification of rhG-CSF with Polyethylene Glycol

采用单甲氧基聚乙二醇(mPEG)修饰重组人粒细胞集落刺激因子rhG-CSF,考察了各因素对蛋白质平均修饰度及体外生物活性的影响,并对修饰产物的稳定保存条件进行了初步探讨.通过四因素四水平正交法和单因素实验结合,优化修饰条件为:PEG与G-CSF摩尔比为25:1,pH7.6的硼酸盐缓冲环境,反应时间40min,反应温度22℃.在此条件下,PEG-G-CSF的平均修饰度为50%,活性可保留40%左右.研究还发现,不同的添加剂影响PEG-G-CSF的保存稳定性,人血清白蛋白和甘露醇是两种效果最好的保护剂,在它们的存在下,PEG-G-CSF溶液在4℃放置一个月后活性保留92%,三个月后保留51%.

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was chemically modified with mPEG. The effects of reaction conditions on modification degree and in vitro bioactivity were investigated by orthogonal design of the experiment. The optimized reaction conditions were found to be borate buffer pH 7.6, molar ratio of PEG to G-CSF 25:1, reaction time 40 min and reaction temperature 22℃. Under the optimized reaction conditions, the bioactivity of PEG-G-CSF retained 40% while the modification degree was 50%. Different formulations had important influence on the storage activity of PEG-G-CSF conjugate. Addition of mannitol and human serum albumin to the solution of PEG-G-CSF could maintain the bioactivity up to 92% for one month and 51% for three months when stored at 4℃.