Purification and characterization of angiotensin I converting enzyme (ACE)inhibitory peptides from Alaska pollack (Theragra chalcogramma) skin

Proteolytic digestion of gelatin extracts from Alaska Pollack (Theragra cha lcogramma) skin brings about a high angiotensin I converting enzyme (ACE) i nhibitory activity. Gelatin extracts were hydrolyzed by serial protease-tre atments in the order of Alcalase, pronase E, and collagenase using a three- step recycling membrane reactor. Fragments arising from the third step were composed of peptides ranging from 0.9 to 1.9 kDa and responsible for ACE i nhibitory activity. Catalytically active two peptides were separated by the consecutive chromatographic methods including gel filtration, ion-exchange chromatography, and reverse-phase high performance liquid chromatography. The isolated peptides were composed of Gly-Pro-Leu and Cry-Pro-Met and show ed IC50, values of 2.6 and 17.13 muM. respectively. These results suggested that Gly-Pro-Leu would be useful as a new antihypertensive agent. (C) 2001 Elsevier Science Ltd. All rights reserved.