重组降血压肽在大肠杆菌中的高效表达

High Expression of Recombinant Angiotensin-converting Enzyme Inhibitory Peptide in E.coli

目的获得具有高活性的重组降血压多肽。方法人工合成高活性降血压肽单体,经酶切位点串联,克隆至表达载体,并转化宿主菌BL21进行诱导表达。结果经酶切、PCR和测序均证明,串联的基因ACEIP已成功克隆至pGEX-4T-2表达载体中,融合蛋白GST-ACEIP的表达水平达24·6%,表达产物的融合蛋白和多肽含量分别为1·1g/L和0·14g/L,其抑制活性达85%。结论已成功制备出高活性的重组降血压多肽,为进一步开发降血压药物奠定基础。

Objective To obtain the recombinant angiotensin-converting enzyme inhibitory peptide（ACEIP） with high biological activity. Methods Synthesize the gene encoding angiotensin-converting enzyme inhibitory peptide, insert into expression vector pGEX-4T-2 and transform to E. coli BL21 for expression. Purify the expressed product by Glutathione Sepharose 4B affinity chromatography and HiTrap Benzmidine FF column chromatography. Determine the expression level of GST-ACEIP fusion protein by thin layer chromatogram scanning, then analyze the protein and polypeptide contents of expressed product by BCA method, and its activity by an improved HPLC method. Results Restriction analysis, PCR and sequencing proved that the target gene was successfully cloned to expression vector pGEX-4T-2. The expression level of GST-ACEIP fusion protein reached 24. 6%. The protein and polypeptide contents of the expressed product were 1.1 g/L and 0. 14 g/L respectively. The inhibiting activity of expressed product to angiotension-converting enzyme was 85%. Conclusion The recombinant angiotensin-converting enzyme inhibitory peptide was successfully prepared. It laid a foundation of further development of drugs for hypertension.