Identification and Action Mechanism of Novel Antioxidative Peptides from Copra Meal Protein

This study aimed to identify novel antioxidant peptides from copra meal protein. The protein was enzymatically digested and properties of released peptides were predicted using in silico approach. The antioxidant activity of peptides was determined using ABTS and DPPH assays. Molecular docking and the isothermal titration calorimetry (ITC) were also used to explore the mechanism of antioxidant peptides scavenging free radicals. The results showed that peptides GMEEER and EEGER scavenged ABTS radical cation with IC50 values of 0.46 +/- 0.067 mmol/L and 6.54 +/- 0.14 mmol/L, and DPPH radicals with IC50 values of 6.98 +/- 0.29 mmol/L and 11.06 +/- 0.18 mmol/L. Hydrophobic interactions and hydrogen bonding were verified as the major driving force for scavenging of free radicals of peptides GMEEER and EEGER by molecular docking and ITC. Especially, the Cterminal residues Arg of two antioxidative peptides might play an important role in scavenging free radical. These findings revealed the antioxidant mechanism of copra meal protein and provided theoretical support for its high-value utilization.