为实现降糖多肽Brevinin-2GUb在大肠杆菌中的高效表达，本文将Brevinin-2GUb基因插入到含有硫氧还蛋白、His标签及肠激酶酶切位点的pET32a载体中，将重组表达载体pET32a-Trx-His-EK-Brevinin-2GUb转化至大肠杆菌中诱导表达Trx-His-EK-Brevinin-2GUb融合蛋白。通过对表达温度进行优化，结果显示16 ℃诱导表达20 h后融合蛋白产量达到36 mg/L；该融合蛋白经肠激酶（EK）特异性切割后成功获得不带标签的Brevinin-2GUb多肽，产量约为2.50 mg/L，纯度达90%以上。通过反相高效液相色谱对重组表达的Brevinin-2GUb进行鉴定，结果显示重组表达的Brevinin-2GUb与人工合成的Brevinin-2GUb的氨基酸序列一致。通过血平板检测发现，170 μg/mL的重组表达Brevinin-2GUb多肽无溶血效应。此外，重组表达的Brevinin-2GUb多肽在浓度为10 μg/mL时对INS-1细胞产生显著的刺激胰岛素分泌作用（为基础释放量的120.04%；p<0.01）。研究结果为Brevinin-2GUb多肽开发为降糖口服液及多肽药物奠定了基础。

In order to achieve high expression of the hypoglycemic peptide Brevinin-2GUb in E. coli, the Brevinin-2GUb gene was inserted into the pET32a vector containing thioredoxin, His tag and enterokinase cleavage site, and then the recombinant expression vector pET32a-Trx- His-EK-Brevinin-2GUb was obtained, which was transformed into E. coli for the fusion protein Trx-His-EK-Brevinin-2GUb expression. Through optimization of its expression temperature, results showed that the fusion protein had the highest yield with 36 mg/L after inducing at 16 ℃ for 20 hours. The Trx-His-EK-Brevinin-2GUb fusion protein was successfully cleaved by enterokinase (EK). The purified Brevinin-2GUb without any tag was obtained with a yield of approximate 2.50 mg/L and the purity ≥90%. The purified Brevinin-2GUb was identified by reversed phase high performance liquid chromatography. The results showed that the amino acid sequence of purified Brevinin-2GUb was consistent with the synthesized Brevinin-2GUb. The purified Brevinin-2GUb peptide had no hemolytic activity toward mammalian cells at the concentration of 170 μg/mL. In addition, purified Brevinin-2GUb produced a significant stimulation of insulin release (120.04% of basal rate; p<0.01) against INS-1 cell lines at a concentration of 10 μg/mL. The results can provide the foundation for the development of Brevinin-2GUb peptide as a hypoglycemic oral solution and a peptide drug.

科技部“863”科技计划项目（2014AA021004）