STRUCTURE AND ACTIVITY OF ANGIOTENSIN-I CONVERTING-ENZYME INHIBITORY PEPTIDES FROM SAKE AND SAKE LEES

Nine peptides to inhibit angiotensin I converting enzyme (ACE) were is olated from sake and sake lees. They were short peptides with 5 or few er amino acid residues, and many of them had a tryptophan or tyrosine residue at the C-terminus. We synthesized the peptide fragments of IYP RY and YGGY, and measured their inhibitory activity. As a result, we h ave concluded that hydrophobic amino acids in the sequence and amino a cid at C-terminus had an important role in the inhibition. When digest ed with pepsin and pancreatin, YGGY lost its inhibitory activity but I YPRY maintained its activity. YGGY and IYPRY were orally administered to spontaneously hypertensive rats (SHR) at the dose of 100 mg/kg. YGG Y didn't change the blood pressure of SHR, but IYPRY reduced their blo od pressure. The hypotensive effect of IYPRY continued for 30 h after administration. Also, three dipeptides among the IYPRY fragments, TY, YP and RY, had hypotensive effects, and the effect of RY continued for 30 h after administration.