The classification and nomenclature of wheat gluten proteins: A reassessment

The nomenclature, relationships and classification of wheat gluten proteins are discussed in relation to recently-reported amino acid sequences of individual components. Although all gliadin and glutenin components show some degree of sequence relationship, three groups of closely related proteins can be recognised. These are high molecular weight (HMW) prolamins (HMW subunits of glutenin), the S-poor prolamins (ω-gliadins) and the S-rich prolamins. The latter group includes gtiadins (α- β-, γ-) and glutenins (LMW subunits). It is concluded that the classical division into gliadins and glutenins is based on a secondary characteristic, the formation of interor intra- molecular disulphide bonds, rather than on homology of the primary amino acid sequences.