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采用聚合酶链式反应 (PCR)法将人酸性成纤维细胞生长因子 (haFGF)基因中编码第 98位和第 132位半胱氨酸 (Cys)的密码子突变为编码丝氨酸 (Ser)的密码子 ,构建重组质粒pET3c haFGFSer98,132 ,转化大肠杆菌BL2 1(DE3) ,表达率达到 2 3 4 8% .用MTT法测定产物的活性 ,发现haFGFSer98,132 突变体的比活与天然haFGF相似 .采用单甲氧基聚乙二醇 (mPEG) 5 0 0 0 -马来酸酰亚胺酯定点修饰第 31位Cys ,修饰率达到 30 %以上 ,修饰产物的比活性保留 5 5 5 3% .
A codon encoding cysteine (Cys) at position 98 and position 132 in the human acidic fibroblast growth factor (haFGF) gene was mutated to a serine (Ser) -secreting codon using polymerase chain reaction (PCR) The recombinant plasmid pET3c haFGFSer98,132 was transformed into E.coli BL21 (DE3) and the expression rate was 23 34%. The activity of the product was determined by MTT assay and the specific activity of haFGFSer98,132 mutant was similar to that of natural haFGF. The mtEG5000 maleate was used to modify the 31st Cys site, the modification rate reached more than 30%, and the specific activity of the modified product remained 553%.