Bile acid micelle disruption activity of short-chain peptides from tryptic hydrolyzate of edible proteins

Abstract

We have investigated the potential of bile acid (BA)-binding short-chain peptides for suppressing cholesterol absorption in the intestine. In our previous report, we have revealed the physicochemical characteristics of high binding peptides using principal component analysis. In this study, we investigated the characteristics of amino acid residues of BA-binding short-chain peptides. We found that short-chain peptides containing lysine (K) and arginine (R) had a higher BA-binding ability than peptides containing other amino acids. Since short-chain tryptic peptides contain K or R residues, we focused on 4-mer, 5-mer, and 6-mer peptides, which were expectedly released from the edible proteins by trypsin. Forty-four short-chain peptides from lactoproteins (Bos taurus) and glutelin (Oryza sativa subsp.Japonica) were synthesized, and their BA micelle disruption activity was evaluated. We could observe such activities in nearly all tested peptides. We found that CEVFR, NGLK, and NSVFR had particularly high disruption activities. We determined that the 50% cholesterol concentration decrease value (DC50) of the micellar solution upon peptide addition was almost the same in case of the aforementioned peptides as that of the VAWWMY as a positive control. In addition, 4-mer and 5-mer peptides had higher BA micelle disruption activity than 6-mer peptides. Our results confirmed that the BA binding and micelle disruption activities were significantly higher if the short-chain peptides contained K and R residues.