Gliadin is a cDNA coding for an epitope-carrying fragment of a wheat gamma-gliadin isoform, having a molecular mass of 18,616 Dalton (high proline content and the low pI are likely causes for the observed discrepancy between calculated molecular weight and the observed electrophoretic mobility of approx. 47 kDa on standard SDS-PAGE), pH 4.6. By sequence design the epitopes correspond to the deamidated neo-epitopes, which in the natural antigen are formed by transglutaminase-mediated glutamine side chain deamidation. Gliadin protein is fused to a hexa-histidine purification tag.