Prolamins are formed as storage proteins in grasses
Prolamins are only present in grasses, such as cereals. They form polymor-phic mixtures of many different subunits of 30 to 90 kDa. Some of these subunits contain cysteine residues and are linked by S-S bridges. Also in glutenins which occur in the grains of wheat and rye, monomers are linked by S-S bridges. The glutenin molecules differ in size. Flour for baking bread depends on the content of high molecular glutenins. Flour from barley, oats or maize that lacks glutenin is not suitable for baking bread. Since the glutenin content is a critical factor in determining the quality of bread grain, investigations are in progress to improve the glutenin content of grains by genetic engineering.