Isolation and Identification of Peptidic α-Glucosidase Inhibitors Derived from Sardine Muscle Hydrolyzate

Abstract We report here the isolation of a-glucosidase (AGH) inhibitory peptides derived from sardine muscle hydrolyzate, which was prepared by digestion with Bacillus licheniformis alka­line protease. As a result of reversed-phase HPLC purification, two AGH inhibitory peptides were isolated from a DEAE -Sephadex A-25 column eluate. The peptides were identified as follows: Val-Trp (IC 50 = 22.6 mᴍ) and Try -Tyr -Pro -Leu (IC 50 = 3.7 mᴍ). AGH inhibitory studies of Try -Tyr -Pro -Leu and its derivatives demonstrated the importance of the tri-peptide chain length as well as the hydrophobic aromatic amino acid tyrosine at the N-terminus, aliphatic amino acids at the C-terminus, as well as an amide proton from the peptide chain at the middle position of the tri-peptide to develop AGH inhibition activity.