VARIATIONS OF WHEAT GLIADIN ANTIGENICITY DURING PEPSIN AND TRYPSIN HYDROLYSIS

To assess changes in the antigenicity of gliadin during proteolysis, t wo model systems of hydrolysis using pepsin or trypsin in the presence of urea or dioxan were tested. Rabbit polyclonal antibodies against w hole gliadin were used in two ELISA procedures. The first one involved direct analysis of antigliadin antibody binding. The second one used anti-immunoglobulin Ci antibodies to indirectly test the antigliadin a ntibodies reacting with hydrolysis products. The antigenicity of pepsi n-hydrolysed gliadin decreased only slowly during hydrolysis and was m aintained at about 45% of the initial value for up to 24 h. Qualitativ ely, after 3 h of hydrolysis, antigenic reactivity pattern seemed to r eveal some marked conformational changes. Tryptic hydrolysis failed to modify significantly the antigenicity in either denaturing agent (ure a or dioxan).