Expression and purification recombinant antihypertensive peptide ameliorates hypertension in rats with spontaneous hypertension

A highly efficient Escherichia coli expression system was established to obtain an appreciable quantity of antihypertensive peptide. The DNA-coding sequence for the Gly-Val-Tyr-Pro-His-Lys peptide was chemically synthesized and linked to form a ten-copy in tandem. It was cloned into the vector pET-15b and expressed in E. coli BL21 (DE3). The optimal conditions for maximal expression were verified and included the induction time and the concentration of isopropyl-β-d-thiogalactopyranoside. The recombinant protein was purified by affinity chromatography to greater than 95% purity, and further purification was achieved by High-performance Liquid Chromatography after cleavage with trypsin. The product was identified by Electrospray Ionization-Mass Spectrometry. The antihypertensive effects of the recombinant AHP were investigated in spontaneously hypertensive rats. The in vivo results demonstrated that a single oral administration of this peptide in spontaneously hypertensive rats resulted in a significant reduction of systolic blood pressure at 2 h. Systolic blood pressure was stabilized 4 h later and remained at a low level for 24 h. This study provides a practical method to develop the peptide into functional foods or drugs for the prevention and treatment of hypertension.