Expression of Milk-Derived Antihypertensive Peptide in Escherichia coli

摘要

Many angiotensin converting enzyme inhibitory pep-tides (ACEIP) have been identified in recent years. Among all the literatures available thus far, almost all the ACEIP were obtained by means of enzymatic hydrolysis. However, little information was available on antihypertensive peptides obtained by DNA recombination technology. In the present paper, our aims were 1) to establish a new method to produce antihypertensive peptides (AHP), and 2) to study the expression profiles of different host strains (Escherichia coli JM109 and DH5α). To achieve these objectives, a DNA fragment encoding the published ACEIP, identified as FFVAPFPEVFGK (known as CEI_(12)) was synthesized, ligated with the expression vector, pQE16, and transformed into E. coli JM109 and DH5α. SDS-PAGE analysis and Western-blotting detection demonstrated that the peptide CEI_(12) (fused with dihydrofolate reductase [DHFR]) was specifically expressed only in E. coli JM109 with IPTG induction. The expression profiles of the AHP CEI_(12) at different IPTG concentrations and different inducing times demonstrated no significant differences by SDS-PAGE analysis. The expression level of CEI_(12) (fused with DHFR) was about 500 μg/ L culture.