Homologies between grain storage proteins of different cereal species. 1. Monoclonal antibody reaction with total protein extracts

Abstract

The interactions of a library of monoclonal antibodies, prepared to wheat ( Triticum aestivum L.) gluten proteins, with extracts of total seed storage protein from a number of related cereals was studied qualitatively using polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and immunoblotting techniques and studied quantitatively using indirect enzyme-immunoassay. Antibodies were of four cross-reaction types: (1) some antibodies, such as many of those binding α- and β-gliadins, bound selectively to wheat grain proteins, (2) others with similar gliadin specificities, bound to prolamins from other Festucoid species (rye, barley and oats), (3) other antibodies specific for certain γ- and ω-gliadins and high-molecular-weight glutenins, bound very well to proteins from wheat, rye and barley grain, while (4) some antibodies showed anomalous cross-reactivities, binding well to wheat and maize prolamins but very weakly to rye or barley grain proteins. These homologies were generally in keeping with structural homologies of proteins from various cereal grains obtained from DNA sequencing and cross-hybridization studies. In some cases, new homologies were identified.