Immunochemical analysis of pepsin-digested fish tropomyosin

A critical step in determining the allergenicity of a food protein is to study the gastrointestinal digestion resistance, which is an essential characteristic of food allergens due to the preservation of their protein structure and immunoglobulin (Ig) E epitopes. In this study, the immunochemical pr...
Ausführliche Beschreibung

A critical step in determining the allergenicity of a food protein is to study the gastrointestinal digestion resistance, which is an essential characteristic of food allergens due to the preservation of their protein structure and immunoglobulin (Ig) E epitopes. In this study, the immunochemical properties of tropomyosin peptide fragments from Atlantic salmon (Salmo salar) and flathead grey mullet (Mugil cephalus) resulted from pepsin digestion were analyzed. To identify the allergens from salmon and mullet, their IgE- and IgG-binding proteins/peptides were studied using fish-allergic human sera and anti-fish protein monoclonal and polyclonal antibodies. From our results, as the major fish allergen, parvalbumin from both species was recognized in all tested human sera. Tropomyosin-bound IgE was identified in 71% of the tested sera. Antigenicity of intact tropomyosin decreased as a function of pepsin digestion time. The amino acid sequence of mullet tropomyosin was analyzed using a tandem mass spectrometer. Two IgE epitopes on Atlantic salmon tropomyosin alpha-1 were mapped. Overall, tropomyosin was identified as one of the major IgE-binding proteins in both fish species; however, further studies are required to determine the clinical significance of fish tropomyosin as an allergen due to its high homology with human tropomyosin. Ausführliche Beschreibung