Chemical nature of a new antihypertensive peptide derived from jellyfish

Abstract

A high-concentration (20%) antihypertensive peptide solution with angiotensin I-converting enzyme (ACE) inhibitory activity was prepared from the powder of the jellyfish Stomolophus nomurai, a plague of which had recently hit Japan's fishing industry, using the drum dryer method. Three active fractions, Fr. 3-1, Fr. 3-3, and Fr. 3-6, were isolated from the peptide mixture by step-wise elution by Sep-Pak Vac C18 and further fractionated by high-performance liquid chromatography twice. The sequences of Fr. 3-1, Fr. 3-3, and Fr. 3-6 were determined as IGDEPLANYL, FGGIDDINQIGQSD, and YYAPFE, respectively. The most active peptide was identified with the synthetic peptide YYAPFE by sequence analysis, MALDITOF MS, and NMR spectra. Further, YYAPFQ, designed and synthesized on the basis of YYAPFE, showed the highest ACE inhibitory activity in vitro among YYAPFE, YYAPF, YYAP, YYA, and YY; however, its effect on systolic blood pressure showed a similar tendency to that of YYAPFE in spontaneously hypertensive rats.