title: Investigations into inhibitor type and mode, simulated gastrointestinal digestion, and cell transport of the angiotensin I-converting enzyme-inhibitory peptides in Pacific hake (Merluccius productus) fillet hydrolysate.
abstract: Fish protein hydrolysate (FPH) produced by incubation of Pacific hake fillet with 3.00% Protamex at pH 6.5 and 40 degrees C for 125 min demonstrated in vitro ACE-inhibitory activity (IC50 = 165 microg/mL), which was enhanced by ultrafiltration through a 10 kDa molecular weight cutoff membrane (IC50 = 44 microg/mL). However, after simulated gastrointestinal digestion, FPH and ultrafiltrate had similar ACE-inhibitory activity (IC 50 = 90 microg/mL), indicating that FPH peptides act as "pro-drug type" inhibitors and that enrichment by ultrafiltration may be unnecessary. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry confirmed that the molecular weights of major peaks were <1 kDa regardless of ultrafiltration. ACE-inhibitory activities of digested hydrolysates were not significantly affected by preincubation with ACE ( P > 0.05) and exhibited a competitive inhibitory mode. A permeability assay using fully differentiated colorectal adenocarcinoma (Caco-2) cells showed an apical to basolateral transport of peptides that ranged from approximately 2 to 20% after 2 h at 37 degrees C. Pacific hake fillet hydrolysates are a potentially bioavailable source of ACE-inhibitory peptides awaiting further in vivo study.
authors.affiliation: Food, Nutrition, and Health Program, Faculty of Land and Food Systems, 2205 East Mall, The University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z4.
authors.forename: Crystal D
authors.initials: CD
authors.lastname: Cinq-Mars
authors.forename: Chun
authors.initials: C
authors.lastname: Hu
authors.forename: David D
authors.initials: DD
authors.lastname: Kitts
authors.forename: Eunice C Y
authors.initials: EC
authors.lastname: Li-Chan
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism* / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport; D018938:Caco-2 Cells; D004063:Digestion; D048388:Gadiformes; D006801:Humans; D006868:Hydrolysis; D008954:Models, Biological; D010194:Pancreatin / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D010455:Peptides; D010194:Pancreatin; D010434:Pepsin A