Abstract: The aims of this work were to establish and optimize the phosphorylation reaction conditions of parvalbumin (PV), the major allergen of silver carp (Hypophthalmichthys molitrix), and to determine the influence of phosphorylation reaction on the structural and immunological properties of PV. Phosphorylation of PV was carried out by dry heating of its mixture with D-glucose-6-phosphate disodium salt hydrate (G6P-Na2) under varying conditions of mass ratio between reactants, reaction time and temperature. The type of polymerization was determined by tricine-SDS-PAGE, and the antigenicity was detected by dot blotting. The microstructure of the obtained polymer was examined by scanning electron microscope (SEM), and its secondary structure and surface hydrophobicity were measured by circular dichroism (CD) spectroscopy and the hydrophobic fluorescence probe 8-anilino-1-naphthalenesulfonate (ANS), respectively. The results indicated that the optimal conditions for phosphorylation reaction of PV were as follows: reaction temperature, 80 ℃; reaction time, 80 min; and ratio of PV to G6P-Na2, 1:4. The aggregate formation and the changes in the secondary structures of G6P-Na2-PV might explain the decrease of PV antigenicity after the phosphorylation reaction. Our present work strongly suggested an effect of phosphorylation on reducing the antigenicity of food allergens.

Key words: parvalbumin, D-glucose-6-phosphate disodium salt hydrate, phosphorylation reaction, antigenicity, secondary structure