Structural Identification and Molecular Interaction Modeling Analysis of Antioxidant Activity Selenium-Enriched Peptides from Selenium-Enriched Pleurotus eryngii.

This study investigated the structure-activity relationships between SePEPs (selenium-enriched peptides) and PEPs (selenium-free peptides) and compared the antioxidant activities of SePEPs and PEPs. The results showed that SePEPs exhibited higher antioxidant activity than PEPs at the same molecular weight, with the molecular weights of 0-3500 Da exhibiting the highest in vitro antioxidant activity. Chelation between selenium and peptides led to a more compact structure and increased particle density in SePEPs. A spectroscopic analysis revealed new peaks and redshifts in SePEPs, along with a higher content of hydrophobic amino acids than PEPs. A molecular interaction modeling analysis indicated that hydrogen bonding and hydrophobic interactions primarily drove the binding between selenium-containing peptides and 1,1-diphenyl-2-picrylhydrazyl (DPPH). Moreover, the solid-phase synthesized MSePGP exhibited significantly greater antioxidant activity than glutathione at high concentrations. At 10 mg/mL, the DPPH radical scavenging rate of MSePGP was 68.5 ± 2.2%. These findings provide a theoretical basis for the design and synthesis of selenium-enriched peptides with enhanced antioxidant properties.