Identification and molecular mechanism of novel antioxidant peptide from fish sauce: A combined quantum chemistry and molecular simulation

Fish sauce, derived from fermented fish, exhibits a notable antioxidant effect after a six-month fermentation process, and we propose that potential antioxidant peptides were present in the fish sauce. We isolated, purified, and identified potential bioactive antioxidant peptides by using fish sauce fermented for 6 months. Additionally, molecular simulation was employed to investigate the antioxidant action mechanism of these bioactive peptides. The molecular docking results revealed that FS4-1 (MHQLSKK), FS4-2 (VLDNSPER), FS4-3 (MNPPAASIK), FS6-1(VLKQAAAGR), and FS6-2 (SPDVSPRR), could dock with the Keap1 receptor. The primary force (Van der Waals' force and hydrogen bonds) and key sites (GLY509 and ALA510) of Keap1 binding to peptides were determined. The active center was located in the side chain of amino acid Met at positions C7H78 and C7H79. We here identified antioxidant peptides in fish sauce and revealed the antioxidant mechanism through molecular simulations. [Display omitted] •Five novel antioxidant peptides were identified from fish sauce.•GLY509 and ALA510 were key binding sites of Keap1-peptides.•H-bonds and van der waals force were the main binding forces for Keap1-peptides.•FS4-3 had the highest antioxidant activity by structure-activity relationship.•C7H78 and C7H79 were active sites in the quantum field.