Glutenin is a heterogeneous family of high-molecular-weight storage proteins found in wheat endosperm, comprising approximately 30-40% of total gluten proteins. These proteins are characterized by repetitive amino acid sequences rich in glutamine and proline, with numerous cysteine residues that form intermolecular disulfide bonds, creating a viscoelastic network essential for dough elasticity and bread-making quality. Unlike gliadins, glutenins are polymeric and insoluble in aqueous alcohols without reducing agents. They contribute to the structural integrity of baked goods by forming a continuous protein matrix during mixing and baking. Molecular weights of subunits range from 30 to 90 kDa for low-molecular-weight glutenins and up to 80-130 kDa for high-molecular-weight types. Glutenin is not a single defined chemical entity but a complex mixture varying by wheat cultivar.