The high molecular weight (HMW) subunits of wheat glutenin are of considerable interest because of their relationship to breadmaking quality. We review recent studies of their genetics, amino acid sequences and conformations, and discuss how they may be assembled to form disulphide-bonded polymers that confer elasticity on wheat dough. We also speculate on how their structure and functionality may be explored using protein engineering and expression in microorganisms or in developing seeds of transgenic plants.