Molecular mechanisms of oyster-derived umami peptides: Docking, dynamics simulation, and MM-PBSA analysis based on optimal enzymolysis.

Oyster umami peptides were valued in food applications, yet critical gaps remain in identifying optimal enzyme species, key peptide, and elucidating T1R1/T1R3 interactions. This study evaluated oyster enzymolysates produced by 8 enzymes, optimized conditions, and investigated umami peptides' mechanisms. Results showed the umami intensity of the enzymolysates was evaluated by electronic tongue with 0.025%-0.3% MSG as the standard control and sensory evaluation. The trypsin-hydrolyzed product exhibited the strongest umami, with a sensory score of 7.73 ± 0.96. The optimized enzymolysis conditions were determined as follows: enzyme dosage of 1%, solid-to-liquid ratio of 1:30, and hydrolysis time of 3 h. Peptidomics identified 4472 peptides, most being umami and mainly derived from Filamin-C, paramyosin, and myosin. Seven peptides (MPSKKKVELK, KEREIQIITK, SKKKVELK, TGVTTGDLKT, AQLRNDKHA, KKPDGTVDVD, EKKIDVK) via molecular docking, electronic tongue, and sensory evaluation showed strong umami. Molecular dynamics simulations confirmed stable peptide-T1R1/T1R3 binding, with AQLRNDKHA, KEREIQIITK, and KKPDGTVDVD showing superior stability. MM-PBSA analysis indicated that electrostatic interactions (mainly mediated by side chains) were the dominant binding force. This study provides direct technical support for the development of natural and highly effective oyster-derived umami enhancers by optimizing the trypsin hydrolysis protocol and identifying high-activity umami peptides. It also establishes a novel integrated workflow for high-throughput screening and elucidating the mechanisms of seafood-derived umami peptides, thereby enriching the diversity of oyster umami peptides and deepening the understanding of their receptor interaction mechanisms.