Identification and Characterization of Glycine- and Proline-Rich Antioxidant Peptides From Antler Residues Based on Peptidomics, Machine Learning, and Molecular Docking.

The purpose of this study was to determine the optimal enzymatic hydrolysis process for antler residues and to identify and characterize the antioxidant peptides present in the products of this hydrolysis. The results indicated that when neutrase is employed as the hydrolase, with an enzyme concentration of 2300 U/g, a temperature of 45°C, a pH of 6.0, a hydrolysis duration of 7.5 h, and a water/material ratio of 15%, the antler residual peptide (ARP) exhibited the highest DPPH clearance rate and degree of hydrolysis. Characterization of the physical and chemical properties revealed that ARP is a mixed antioxidant peptide rich in glycine and proline, with 93.6% of its composition consisting of peptides with a molecular weight of lower than 1 kDa. Furthermore, 21 antioxidant peptides were successfully identified from ARP using peptidomics and machine learning techniques. FM7, GPG10, and PP9 demonstrated advantages such as non-toxicity, solubility in water, cell penetration, and the absence of digestive enzyme action sites. Additionally, molecular docking results showed that the binding energies of FM7, GPG10, and PP9 with Keap1 were 9.5, 8.5, and 10.8 kcal/mol, respectively, suggesting that these three antioxidant peptides may exert their antioxidant effects through the Nrf2/Keap1 pathway.