Biochemical, Genetic, and Molecular Characterization of Wheat Glutenin and Its Component Subunits

Abstract

Of all the cereal grains, wheat is unique because wheat flour alone has the ability to form a dough that exhibits the rheological properties required for the production of leavened bread and for the wider diversity of foods that have been developed to take advantage of these attributes. The unique properties of the wheat grain reside primarily in the gluten-forming storage proteins of its endosperm. It is these dough-forming properties that are responsible for wheat being the most important source of protein in the human diet. The bread and durum wheats are polyploid species containing three (AABBDD) and two (AABB) related genomes, respectively. The genetic constitution of wheat is important because all quality traits result from the expression of genes and their interaction with the environment. The full spectrum of wheat-endosperm proteins has been exhibited in proteome studies involving the two-dimensional fractionation of the polypeptides (after disulfide-bond rupture), followed by dissection of the individual components for identification. This display (Fig. 1) shows that there are at least 1,300 polypeptides, over 300 of which have been identified by N-terminal amino