Investigation of the mechanism of H2O2 combined pulsed electric field treatment reducing the antigenicity of parvalbumin and tropomyosin by high-resolution mass spectrometry, molecular dynamics and DFT computation

Abstract

The mechanism of H₂O₂ combined pulsed electric field (PEF) treatment stimulating oxidation and decreasing allergenicity of parvalbumin of grass carp and tropomyosin of king prawn was clarified. Compared to H₂O₂ treatment alone, the IgG-binding capacity of parvalbumin and tropomyosin significantly decreased by 21.87 % and 81.18 % after H₂O₂ combined PEF treatment, while the IgE binding capacity reduced by 63.42 % and 76.91 %. •OH caused by electrochemical reaction triggered oxidative degradation of protein and disrupted their allergenic epitopes, which resulted in the structural unfolding, hydrophobic quenching and prevented the recognition by related antibody. Molecular dynamics showed that H₂O₂ combined PEF treatment promoted •OH interaction with surface residues than alone H₂O₂ treatment and PEF treatment, where the H₂O₂ treatment and H₂O₂ combined PEF treatment caused significant structural alterations of tropomyosin, which greatly converted α-helix to random coil. Furthermore, density functional theory calculation revealed that hydrogen abstraction at C_α rendered more stable intermediates where the spin density of the unpaired electron was lower, while alcohol formed by addition of •OH to the side chains was pretty stable but their phenyl and imidazolyl states were more preferred than the saturated side-chains-containing ones.