Polyacrylamide gel-urea electrophoresis of cereal prolamins at acidic pH

An electrophoretic procedure is described for vertical polyacrylamide gel-urea electrophoresis of cereal prolamins. The polyacrylamide gel is directly polymerized in potassium lactate buffer, pH 3.6, with an ammonium persulfate-silver nitrate system of catalysts, which enables one to control the polymerization of acrylamide. Electrophoresis is performed in aluminum lactate buffer, pH 3.6. Thus proteins are separated in a discontinuous system of buffers, which allows sample concentration at the beginning of the electrophoresis.Because the system acts in a very dissociating medium (6 m urea), any type of prolamins (e.g., gliadin, secalin, hordein, avenin, or zein) can be simultaneously analyzed and compared on the same gel slab. On the other hand, as is shown with barley prolamins, improved resolution is obtained, without any sample-reducing requirement during the same run, for both typical hordeins (B- and C-hordeins) and fast-moving low-molecular-weight proteins (A-polypeptides).