Investigations into Inhibitor Type and Mode, Simulated Gastrointestinal Digestion, and Cell Transport of the Angiotensin I-Converting Enzyme–Inhibitory Peptides in Pacific Hake (Merluccius p
文摘
Fish protein hydrolysate (FPH) produced by incubation of Pacific hake fillet with 3.00% Protamex at pH 6.5 and 40 °C for 125 min demonstrated in vitro ACE-inhibitory activity (IC50 = 165 µg/mL), which was enhanced by ultrafiltration through a 10 kDa molecular weight cutoff membrane (IC50 = 44 µg/mL). However, after simulated gastrointestinal digestion, FPH and ultrafiltrate had similar ACE-inhibitory activity (IC50 = 90 µg/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 ~2 to 20% after 2 h at 37 °C. Pacific hake fillet hydrolysates are a potentially bioavailable source of ACE-inhibitory peptides awaiting further in vivo study.