Angiotensin I converting enzyme (ACE) inhibitory peptides were investigated in the head and liver of chum salmon and the digestive gland of scallop.

After these tissues were hydrolyzed by commercial proteases for food, the ACE inhibitory activity of hydrolysates was measured. The hydrolysates of chum salmon head produced with BIOPURASE showed the most potent inhibitory activity.

This hydrolysates was separated into fractions using ODS resin. Each eluted with 10, 30, 50% ethanol showed inhibitory activity. The most active fraction was that eluted with 50% ethanol; it showed 50% inhibition for ACE at 78μg/ml. The molecular weight of this fraction was estimated to be 500-3,000 from the results of high-performance gel chromatography analysis Furthermore, amino acid analysisi showed that these inhibitors contained large quantities of glycine, lysine, and leusine