Abstract:In order to evaluate the gastrointestinal tolerance of a new Alaska pollock skin collagen-derived metal chelating peptide (Ala-Gly-Pro-Ala-Gly-Pro-Arg, peptide M), an in vitro simulated gastrointestinal digestion (SGID) model was established, and this model included two stages: simulated human gastric digestion and simulated human intestinal digestion. The calcium-chelating activity of peptide M was 0.88 ± 0.02 μg/mg, and its iron-chelating activity was 33.67%. The calcium-chelating activity of gastric digestion product S was 0.87 ± 0.03 μg/mg, a 1.14% decrease compared to the pure peptide. The iron-chelating activity of S was 33.72%, an increase of 0.05% compared to the pure peptide. The calcium-chelating activity of intestinal digestion product D was 0.85 ± 0.01 μg/mg, a 3.40% decrease compared to the pure peptide. And the iron-chelating activity of D was 34.13%, an increase of 0.46% compared to the pure peptide. Reversed-phase high-performance liquid chromatography, full scan mass spectrometry, and circular dichroism showed that after two-stage SGID, M molecule did not show a change in molecular mass or cleavage of peptide bonds, but there were changes in the conformation, including a decrease in the proportion of random coils and increases in the proportions of β-sheets and β-turns. Therefore, during the SGID, the amino acid composition in the peptide was not changed, and the spatial conformation was changed. The calcium- and iron-chelating capabilities were not significantly changed. Peptide M showed a high gastrointestinal tolerance in SGID.
