Synthesis of peptides related to the prosegment of mouse submaxillary gland renin precursor: an approach to renin inhibitors.

The complete sequence of the structural gene coding for mouse submaxillary gland renin was recently reported and the amino acid sequence of preprorenin was deduced. This sequence includes a 45-amino acid peptide that corresponds to the prosegment of the renin precursor. To investigate whether peptides related to the renin prosegment are able to inhibit renin activity, we have synthesized four peptides having the following structures: Arg-Ile-Pro-OMe, butyloxycarbonyl(Boc)-Leu-Lys-Lys-Met-Pro-OMe, Boc-Arg-Ile-Pro-Leu-Lys-Lys-Met-Pro-OMe, and Boc-Glu-Arg-Ile-Pro-Leu-Lys-Lys-Met-Pro-OMe (corresponding to amino acids 12-14, 15-19, 12-19, and 11-19, respectively, of the renin prosegment). All four peptides were found to inhibit the activity of pure mouse submaxillary renin on a porcine synthetic tetra-decapeptide in vitro, and the most potent inhibitors exhibited IC50 values in the micromolar range. Enzymatic kinetic studies carried out using peptide 15-19 showed an uncompetitive or a mixed type of inhibition with a Ki value of 2.3 X 10(-6) M at 37 degrees C in 0.5 M citrate/phosphate buffer (pH 6.0).