Preparation of gliadin by urea extraction

A method in which, after a preliminary water extraction, all the gluten proteins in flour may be extracted by 2M urea is described. The protein so extracted is mainly gliadin, relatively free from high‐molecuiarweight glutenin. Gel filtration with Bio Gel P‐150 polyacrylamide beads and electrophoresis in starch gel of varying porosity shows that the molecular weight distribution is relatively narrow. It is suggested that, under some conditions, an unidentified compound of low molecular weight is responsible for the intermolecular crosslinking of gliadin molecules to give high‐molecular‐weight glutenin.