title: A quantitative in silico analysis calculates the angiotensin I converting enzyme (ACE) inhibitory activity in pea and whey protein digests.
abstract: Angiotensin I converting enzyme (ACE) inhibitory peptides can induce antihypertensive effects after oral administration. By means of an ACE inhibitory peptide database, containing about 500 reported sequences and their IC(50) values, the different proteins in pea and whey were quantitatively evaluated as precursors for ACE inhibitory peptides. This analysis was combined with experimental data from the evolution in ACE inhibitory activity and protein degradation during in vitro gastrointestinal digestion. Pea proteins produced similar in silico scores and were degraded early in the in vitro digestion. High ACE inhibitory activity was observed after the simulated stomach phase and augmented slightly in the simulated small intestine phase. The major whey protein beta-lactoglobulin obtained the highest in silico scores, which corresponded with the fact that degradation of this protein in vitro only occurred from the simulated small intestine phase on and resulted in a 10-fold increase in the ACE inhibitory activity. Whey protein obtained total in silico scores of about 124 ml/mg, compared to 46 ml/mg for pea protein, indicating that whey protein would be a richer source of ACE inhibitory peptides than pea protein. Although beta-lactoglobulin is only partially digested, a higher ACE inhibitory activity was indeed found in the whey (IC(50) = 0.048 mg/ml) compared to the pea digest (IC(50) = 0.076 mg/ml). In silico gastrointestinal digestion of the highest scoring proteins in pea and whey, vicilin and albumin PA2, and beta-lactoglobulin, respectively, directly released a number of potent ACE inhibitory peptides. Several other ACE inhibitory sequences resisted in silico digestion by gastrointestinal proteases. Briefly, the quantitative in silico analysis will facilitate the study of precursor proteins on a large scale and the specific release of bioactive peptides.
authors.affiliation: Laboratory of Microbial Ecology and Technology, and Department of Food Technology and Nutrition, Faculty of Agricultural and Applied Biological Sciences, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
authors.forename: Vanessa
authors.initials: V
authors.lastname: Vermeirssen
authors.forename: Arie
authors.initials: A
authors.lastname: van der Bent
authors.forename: John
authors.initials: J
authors.lastname: Van Camp
authors.forename: Aart
authors.initials: A
authors.lastname: van Amerongen
authors.forename: Willy
authors.initials: W
authors.lastname: Verstraete
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D002417:Cattle; D019295:Computational Biology; D008894:Milk Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D013997:Time Factors; D000067816:Whey Proteins
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D008894:Milk Proteins; D010446:Peptide Fragments; D000067816:Whey Proteins; D007703:Peptidyl-Dipeptidase A