Immunochemical studies on barley seed storage proteins : The specificity of an antibody to 'C' hordein and its reaction with prolamins from other cereals.

The antigenic relationships between the prolamins of barley, rye and wheat have been studied by examining the specificity of an antibody to 'C' hordein in a quantitative study using a laser nephelometer. The antibody reacts weakly with 'B' hordein and strongly with 75-kdalton and 40-kdalton γ-secalins from rye and γ3 some ω-gliadins from wheat. Absorption experiments and immunodiffusion tests indicate that there are shared antigenic determinants for most of the prolamins. All the species with reacting prolamins belong to the sub-family Festucoideae of the Gramineae. The prolamins of maize, pearl millet and sorghum, species of the sub-family Panicoideae, do not react. The results confirm the known lack of homology between the prolamins of the two sub-families and also indicate the presence of relationships not yet established between 'C' hordein, the 75-kdalton and 40-kdalton γ-secalins and also γ3 gliadin.