Egg Yolk Selenopeptides: Preparation, Characterization, and Immunomodulatory Activity

Identification, characterization, and molecular docking of immunomodulatory peptides in Astragalus (Astragalus membranaceus (Fisch.)Bge) seed protein hydrolysates

Developing bioactive peptides from natural plant sources into functional foods and immunomodulators is becoming an attractive approach. In this study, the protein hydrolysates (APH) of Astragalus membranaceus (Fisch.)Bge seed was prepared by alkaline protease digestion method, and components with less than 3KDa were obtained by ultrafiltration (UAPH). The peptide sequence of UAPH was identified by UPLC-MS/MS. silico analysis screened 46 peptides with biological activity. Cell experiments and molecular docking results showed that UAPH can regulate the immune activity of RAW264.7 cells by enhancing cell phagocytic activity and ROS generation, upregulating the expression of TNF -α, IL-6, IL-1β, and TLR4. Peptides DWVSLPG, WVSLPGVP, and FTSIVGNVF are expected to contribute to the immune regulatory activity of UAPH. This study first discovered that the hydrolyzed protein of A. membranaceus seed is a source of immunomodulatory agents, revealing the potential of A. membranaceus seed peptides in developing novel and effective immunomodulatory functional foods.

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.

Synergistic immunomodulatory effect of wheat/soybean/sea cucumber peptides in chloramphenicol induced immunosuppression zebrafish

BACKGROUND

Food-derived immunomodulatory peptides serve as vital agents in promoting health by protecting the body against pathogens. The present study focused on determining the optimal ratio for combining different peptides to form a complex that enhances immune activity in immunosuppressed zebrafish.

RESULTS

We established a method for immunosuppression in zebrafish, discovering that treatment with 125 μg mL-1 chloramphenicol significantly decreased the macrophage number and neutrophil fluorescence intensity. We then assessed the immunomodulatory activity of soft-shelled turtle peptides, sea cucumber peptides (SCP), black-bone silky fowl peptides, soybean peptides (SP), wheat peptides (WP), whey protein peptides and casein hydrolysate peptides. The results of individual peptides showed that WP uniquely increased the interferon-γ level, SP most effectively increased neutrophil fluorescence intensity, and SCP increased both macrophage number and neutrophil fluorescence intensity. Using mixture design and fuzzy comprehensive evaluation methods, we identified a synergistic mixture peptides: 8.32% SCP + 20.84% SP + 70.84% WP, which had the highest score in the fuzzy comprehensive evaluation, making it the best blend for boosting zebrafish immunity.

CONCLUSION

A specific mixture of peptides (8.32% SCP + 20.84% SP + 70.84% WP) holds potential as a result of a synergistic immunomodulatory effect. © 2025 Society of Chemical Industry.

Pyro-Thermolysis Pattern Analysis of Selenopeptide in Selenium-Enriched Rice Based on Two-Dimensional Dietary Kinetics Evolution

Selenopeptides can be ideal dietary selenium (Se) supplements for humans. Currently, rice is not used much as a source of selenopeptides. Here, we executed the selenopeptidomics analysis of selenium-enriched rice protein hydrolysates using the full MS-dd-MS2 acquisition method and identified selenopeptides, including L{Se-Met}AK and other selenopeptides. Specifically, selenomethionine (SeMet) replaced methionine (Met) in the rice protein-Oryzain alpha chain (EC: 3.4.22) and generated a selenopeptide L{Se-Met}AK (molecular formula: C20H38N5O5Se) during subsequent protein hydrolysis. This selenopeptide was in 425-428 amino acid residues of the Oryzain alpha chain. Thermal processing led to selenopeptide cleavage, which affected the efficient retention of selenopeptides. Activation energy (Ea) was used to locate the quality control markers in the thermal degradation of selenopeptides. Therefore, this study established the thermal degradation rate equation for the selenopeptide L{Se-Met}AK at 100 °C, 110 and 120 °C; and identified the pyrolysis products, including L{Se-Met}A, LMA, LMAK, K1, and K2, involving C-N cleavage on the amide bond of alanine and lysine, C-Se bond cleavage and C-N cleavage on the amide bond of alanine and Met; the fit coefficients of the thermal reaction models were ≥0.9248, which could accurately quantify the real-time pyrolysis kinetic process; and LMAK had a lower Ea of 88.20 kJ/mol, which made it easier to produce. In summary, LMAK can be used as a quality control marker in the pyrolysis process, providing technical support for the efficient retention of selenopeptides.

Co-Immobilization of Alcalase/Dispase for Production of Selenium-Enriched Peptide from Cardamine violifolia

Enzymatically derived selenium-enriched peptides from Cardamine violifolia (CV) can serve as valuable selenium supplements. However, the industrial application of free enzyme is impeded by its limited stability and reusability. Herein, this study explores the application of co-immobilized enzymes (Alcalase and Dispase) on amino resin for hydrolyzing CV proteins to produce selenium-enriched peptides. The successful enzyme immobilization was confirmed through scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR). Co-immobilized enzyme at a mass ratio of 5:1 (Alcalase/Dispase) exhibited the smallest pore size (7.065 nm) and highest activity (41 U/mg), resulting in a high degree of hydrolysis of CV protein (27.2%), which was obviously higher than the case of using free enzymes (20.7%) or immobilized Alcalase (25.8%). In addition, after a month of storage, the co-immobilized enzyme still retained a viability level of 41.93%, showing fairly good stability. Encouragingly, the selenium-enriched peptides from co-immobilized enzyme hydrolysis exhibited uniform distribution of selenium forms, complete amino acid fractions and homogeneous distribution of molecular weight, confirming the practicality of using co-immobilized enzymes for CV protein hydrolysis.