The activity of single gliadin components in a foetal chick intestine assay for coeliac disease

Abstract

 Although gliadins are known to induce coeliac disease, the toxicity of single gliadin components is still uncertain. Therefore, the main components of ω-, α- and γ-type gliadins from the wheat cultivar Rektor were preparatively separated by RP-HPLC. Purity and type of the isolated components (one ω-, eight α- and four γ-gliadins) were confirmed by N-terminal amino acid sequencing. Gliadin components were digested with immobilised pepsin and trypsin and 0.5 mg of dialysed hydrolysates was tested with a foetal chick intestine assay which has been proven to be specific for the coeliac toxic effect of total gliadin and enzymatic hydrolysates. The reduction in sucrase activity was compared with a control culture and was taken as an indicator for toxicity. The results demonstrated that all the gliadin components studied remarkably reduced the increase in sucrase activity to 23–68% of the control assays. Important differences in the inhibitory action between the three gliadin types could not be detected, and only in a few cases did the single components differ significantly. Based on these results, it seems impossible to remove the toxic factor of gliadins by plant breeding.