No 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 C 18 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, MALDI-TOF 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.