The regulatory mechanism of pulsed electric field (PEF) targeting at C-terminal glutamine of shrimp antioxidant peptide QMDDQ based on MD simulation

Abstract The possible mechanism was investigated for the antioxidant activity improvement on a novel peptide QMDDQ obtained from shrimp protein by PEF in this study. It was found that QMDDQ that treated under 40 kV/cm exhibited the best antioxidant activity. After PEF treatment, the primary structure of QMDDQ was not influenced, while the β-sheet content was decreased and the random coil content was correspondingly increased in PEF-treated QMDDQ solution. The cross peak between CαH (4.53 ppm) on 4-Asp and CγH (1.78 ppm) on 5-Gln residue disappeared in PEF-treated peptide. After applying PEF treatment, the side chain of C-terminus residue Glutamine at was stretched to expose more active sites to combine with free radicals, thus enhancing the scavenging effect of radical. Hence, the antioxidant activity improvement of QMDDQ might be attributed to the targeted regulation of PEF treatment at C-terminal.