DIGESTION OF PEPTIDES FROM SARDINE MUSCLE THAT INHIBIT ANGIOTENSIN-I CONVERTING ENZYME BY INTESTINAL ENZYMES OF PIGS

Three peptides (I : Leu-Lys-Leu, II : Val-Lys-Ala-Gly-Phe, and III : Lys-Val-Leu-Ala-Gly-Met) from a hydrolyzate of sardine muscle and that inhibited angiotensin I converting enzyme were digested with the intestinal fluid of pigs. The IC50 values of II and III were decreased to 56% and 66% of the original value, respectively, after digestion. Peptide I was not digested. Five peptide fragments were isolated from the peptide digests by high-pressure liquid chromatography. By the Edman procedure, peptide II digest was found to contain the fragments Val-Lys-Ala-Gly and Gly-Phe, and peptide III digest was found to contain the fragments Ala-Gly-Met, Lys-Val-Leu-Ala-Gly, and Lys-Val-Leu.