人纤溶酶原Kringle 1—4.5结构域的表达及活性鉴定

利用RT PCR的方法从人肝癌细胞株HepG2细胞内获得了编码人纤溶酶原 (hPlasminogen)的Kringle 1到 4及部分Kringle 5结构域 (简称K1- 4.5 )的cDNA ,将其克隆到表达载体pHIL S1中。将重组载体pHIL K 1- 4.5转化毕赤酵母GS115 ,得到的重组菌株用甲醇进行诱导表达 ,并利用赖氨酸亲和柱纯化重组蛋白质 ,得到的蛋白质纯度大于 95 %。重组蛋白质能特异性地按剂量依赖的方式抑制碱性成纤维细胞生长因子 (bFGF)刺激的牛主动脉内皮细胞 (BAEC)的增殖 ,浓度为 2mg/L达到最大抑制效果的 5 0 % ;K1- 4.5还能抑制bFGF引起的BAEC的迁移 ,作用浓度为 1mg/L时对BAEC迁移的抑制率为 40 %。

Expression and Characterization of Kringle 1-4.5 Domains of Human Plasminogen

The cDNA encoding Kringle 1-4 and part of Kringle 5 domains of human plasminogen (K1-4.5), obtained from HepG2 by RT-PCR, was cloned into expression vector pHIL-S1. The recombinant plasmid pHIL- K 1-4.5 was transformed into Pichia pastoris GS115 and the recombinant yeast was induced to express the recombinant proteins by methanol. The expressed proteins were purified by lysine affinity chromatography to a purity of 95%. The recombinant K1-4.5 inhibited the growth of bovine capillary endothelial cells (BAEC) stimulated by the basic fibroblast growth factor (bFGF), in a dosage-dependent manner with a half maximal concentration of 2 mg/L. rhK1-4.5 also inhibited 40% of the BAEC migration stimulated by bFGF in the concentration of 1 mg/L.