Structures and Activity of Angiotensin-converting Enzyme Inhibitors in an α-Zein Hydrolysate

Abstract

Peptides that inhibit angiotensin-converting enzyme (ACE) were isolated from α-zein hydrolysate prepared with thermolysin. Their chemical structures were identified by Edman degradation and fast-atom bombardment mass spectrometry. Most of them were found to be tripeptides such as Leu-Arg-Pro, Leu-Ser-Pro, and Leu-Gin-Pro, having IC50 values of 0.27, 1.7, and 1.9 µM, respectively. These peptides were synthesized by a solid phase procedure and had similar ACE inhibitory activities as the isolated inhibitors. The hypotensive activity of Leu-Arg-Pro on spontaneously hypertensive rats was also investigated, with the result that the blood pressure decreased by 15 mmHg after a 30mg/kg intravenous injection. © 1991, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.