Lin Zheng

This study compared the anti-fatigue tetrapeptide YGLF with an equimolar amino acid (AA) mixture across three stages: postingestion absorption, postexercise fatigue, and muscle damage repair. Despite rapid in vitro degradation (<1% intact), YGLF elevated plasma AAs more effectively than the AA mixture 15 min postingestion (51.97 vs 46.34 mg/100 mL). Postexercise, YGLF outperformed the AA mixture by further increasing muscle AAs and blood glucose, reducing metabolic byproducts, and activating AMPK. Following muscle damage, transcriptomics revealed that the AA mixture primarily modulated energy metabolism, whereas YGLF uniquely upregulated muscle growth genes. Western blotting confirmed that YGLF promoted repair via the Sestrin2/mTOR and Pax7/MYOD pathways. These findings demonstrate the distinct bioactivity of YGLF over that of free AAs, establishing a rationale for utilizing specific peptides in sports nutrition and muscle recovery.

Casein hydrolysate (CMH) was proved to exert strong sleep-enhancing effects by vital amino acid metabolisms, GABAergic system, and cAMP signaling pathway in our previous study. Whether there existed a novel active peptide in CMH and its underlying synergic mechanism remain unknown. This study aims to explore novel potent sleep-enhancing peptides in CMH and to systematically investigate its underlying mechanisms by multiomics analysis. Our results showed that many potent sleep-enhancing Tyr-based peptides were released by CMH. Considering potential structural features and contents, YQEPVLGPVR (YQ10) was screened, which significantly prolonged sleep duration and recovered the corticosterone level. Moreover, ten crucial DEGs and DEMs were revealed by omics analysis. YQ10 might regulate CaMKII and neuroinflammatory pathways to communicate with GABAergic and cAMP signaling pathways, particularly regulating CaMKII, IL-1β, and IL-6, which was validated by vital factors/protein expressions and antagonist experiments. These findings could provide a theoretic basis to explore potential sleep-enhancing mechanisms of Tyr-based peptides.

To achieve targeted enzymatic hydrolysis of whey protein and uncover the intrinsic mechanisms underlying the reduction in antigenicity during enzymatic hydrolysis, this study integrated bioinformatics prediction, structural characterization, and peptide mass fingerprinting to systematically analyze whey protein hydrolysates. A total of 17 and 24 linear antigenic epitopes were predicted, and five proteases were selected for hydrolysis based on the key amino acid composition of epitopes and protease cleavage preferences. Compared with other proteases, Alcalase and Papain demonstrated superior degradation capacity for α-LA and β-LG, significantly increasing the proportion of hydrolyzed fragments below 1 kDa and exhibiting lower residual antigenicity. Peptide mass fingerprinting analysis revealed that proteases achieve precise degradation of antigenic epitopes by specifically recognizing key amino acids such as leucine, lysine, and glutamic acid and cleaving peptide bonds, thereby reshaping the peptide profile through removal of long peptides associated with important epitopes and ultimately reducing antigenicity.

Whey protein hydrolysate enriched in branched-chain amino acid-containing oligopeptides improves age-related muscle strength weakness by stimulating enhanced muscle synthesis and organelle membrane renewal.

This study aimed to investigate the protective effects of bovine myocardium hydrolysates prepared from different protein fractions on H₂O₂-induced myocardial injury in H9c2 cells and to develop an effective way to explore potential myocardial protective peptides. Results showed that, as compared with bovine heart and its water-soluble protein fraction, myocardium hydrolysate prepared from salt-soluble protein fraction demonstrated better myocardial protective activity, significantly increasing cell viability and activities of antioxidant enzymes (SOD and CAT), while reducing contents of myocardial injury markers (LDH, CK-MB, and cTnT). Ten novel myocardial protective peptides (FR, LK, LPF, RVL, SLL, FDIF, FQPS, GLPPILN, SEAPPHIF, and TEAPLNPK) were identified following a peptidomics-activity guided strategy integrating multivariate analysis and a random forest model. Molecular docking analysis revealed potential molecular mechanisms that might act on myocardial injury-related targets such as AKT1, STAT3, and MMP9. This study may provide insights for the rapid identification of food-derived myocardial protective peptides.

Katsuwonus pelamis hydrolysates prepared by Papain showed stronger renoprotective effects, with Val-Lys identified as a novel renoprotective peptide by integrated peptidomics, multivariate analysis, random forest, and quantitative analysis.