中文摘要：

人三叶因子2（hTFF2）具有促进细胞迁移和抑制细胞凋亡的活性, 所以被认为是胃肠黏膜修复的启动者之一。因为从人组织中获得hTFF2比较困难, 而且体外产生的重组hTFF2大都以融合蛋白的形式存在, 所以该研究的目的是在体外产生不带任何融合蛋白的游离型hTFF2。hTFF2的开放阅读框被插入pET-32a（＋）表达载体, 然后在大肠杆菌中表达出带有硫氧还蛋白融合部分的hTFF2融合蛋白。进而利用融合蛋白的组氨酸标签使用镍亲和色谱柱以及反向高压色谱柱对目的蛋白进行纯化。23 °C, FXa因子裂解纯度高达95%的融合蛋白以得到游离型hTFF2。在去除FXa因子和尚未被切开的融合蛋白后, 获得的游离型hTFF2被SDS-PAGE和Western blotting所证实。重组游离型hTFF2的产量约为5 mg/L, 并且hTFF2能促进IEC-6细胞的迁移以及体外的伤口修复, 而这些活性是依赖于ERK1/2的激活。同时, hTFF2也能抑制50 μmol/L神经鞘氨醇所引起的HCT-116细胞的凋亡。总之, 研究结果表明，在大肠杆菌中高产量地成功表达出具有生物学活性的游离型hTFF2, 这为研究TFF2的分子机制, 以及研制和开发TFF2的相关药物都提供很大的帮助。

英文摘要：

Human trefoil factor 2 （hTFF2） is considered as one of the most important initiators of mucosal healing in the gastrointestinal tract by promoting cell migration and suppressing apoptosis. However, it is hard to obtain hTFF2 from human tissue and many recombinant hTFF2 produced in vitro exist as fusion proteins. The purpose of the present study was to produce native hTFF2 while maintaining its biological activities. The open reading frame of hTFF2 was inserted into a pET-32a（＋） expression vector, and hTFF2-TRX fusion protein was successfully expressed in Escherichia coli and purified by Nickel-nitrilotriacetic acid affinity chromatography and reverse-phase HPLC steps. The recombinant fusion protein （purity〉95%） was cleaved by Factor Xa at 23 ~C to release hTFF2. After removal of Factor Xa and undigested fusion proteins, hTFF2 was purified and identified by SDS-PAGE and Western blotting. The yield of recombinant hTFF2 was about 5 mg/L. The recombinant hTFF2 could promote IEC-6 cells migration and in vitro wound healing via the activation of ERK1/2. Recombinant hTFF2 could also inhibit apoptosis of HCT-116 cells induced by 50 lamol/L ceramide In summary, our results showed that the recombinant hTFF2 was expressed in E. coli and successfully purified after cleavage with the fusion partner with high yield while maintaining its biological activities. Recombinant hTFF2 might be useful for investigating the molecular mechanism of hTFF2 and development of hTFF2-related drugs.