Digestibility and IgE-Binding of Glycosylated Codfish Parvalbumin

Abstract

Food-processing conditions may alter the allergenicity of food proteins by different means. In this study, the effect of the glycosylation as a result of thermal treatment on the digestibility and IgE-binding of codfish parvalbumin is investigated. Native and glycosylated parvalbumins were digested with pepsin at various conditions relevant for the gastrointestinal tract. Intact proteins and peptides were analysed for apparent molecular weight and IgE-binding. Glycosylation did not substantially affect the digestion. Although the peptides resulting from digestion were relatively large (3 and 4 kDa), the IgE-binding was strongly diminished. However, the glycosylated parvalbumin had a strong propensity to form dimers and tetramers, and these multimers bound IgE intensely, suggesting stronger IgE-binding than monomeric parvalbumin. We conclude that glycosylation of codfish parvalbumin does not affect the digestibility of parvalbumin and that the peptides resulting from this digestion show low IgE-binding, regardless of glycosylation. Glycosylation of parvalbumin leads to the formation of higher order structures that are more potent IgE binders than native, monomeric parvalbumin. Therefore, food-processing conditions applied to fish allergen can potentially lead to increased allergenicity, even while the protein's digestibility is not affected by such processing.

Evaluation of the IgE reactivity of common pandora parvalbumin in a Moroccan population and action of heating and enzymatic treatments

“…These results were confirmed by dot-blot assay, showing that the intensity of spots became weak in 11 patients tested. Several studies are consistent with our findings which indicate the reduction of the allergenicity of fish parvalbumin by enzymatic digestion processing (Cai et al, 2010;De Jongh et al, 2013;Untersmayr et al, 2003). Those results suggest that the CPP epitopes recognized by human IgE are partially conformational, while remaining binding of pepsin digested CPP to human IgE indicated that a large part of epitopes involved were sequential.…”

Fibril Formation from Pea Protein and Subsequent Gel Formation

“…The spectrum of native pea protein showed two minima around 222 and 208 nm and a zero crossing at 204 nm, indicative of a secondary structure that is highly predominated by α-helical and some β-sheet contributions. 35 Upon heating of pea protein at pH 2.0, a shift at the zero crossing to 197 nm was observed, illustrating a considerable loss of β-sheet strands. Substantial amounts (about 20%) of β-sheet were, however, still present in pea protein heated at pH 2.0 when the far-UV CD spectra were analyzed by the method previously described.…”

Shellfish Tropomyosin IgE Cross‐Reactivity Differs Among Edible Insect Species

“…A protein ladder, Precision Plus Protein Dual Xtra standards (Biorad, Hercules, CA, USA), was used to estimate molecular weight. Immunoblotting was performed as described elsewhere using rabbit anti‐shrimp TM IgG (Indoor Biotechnologies, Charlottesville, VA, USA), [ 15 ] plasma, or sera each diluted in 2.5% non‐fat dry milk in PBS with tween (0.05% Tween 20, 1x PBS, pH 7.4). Rabbit anti‐shrimp TM IgG was diluted 1:4000 followed by 1:4000 goat anti‐rabbit IgG peroxidase conjugated (Thermo Scientific, Waltham, WA, USA) and sera or plasma were diluted 1:10 followed by 1:1000 mouse anti‐human IgE peroxidase conjugated (Southern Biotech, Birmingham, AL, USA).…”