Cereal Chem 58:275 - 281.  |  VIEW ARTICLE
Maize Endosperm Proteins Compared by Sodium Dodecyl Sulfate Gel Electrophoresis and Isoelectric Focusing.

C. M. Wilson, P. R. Shewry, and B. J. Miflin. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

Maize endosperm proteins were extracted by variations of the Osborne procedure. The protein components of each fraction were compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis and isolectric focusing. The salt-soluble fraction and the glutelins consisted of a large number of proteins with only a few bands in common. Only one of the glutelin bands was present in a large amount, and we do not consider this fraction to consist of true storage proteins. The zein fraction produced two major bands by gel electrophoresis but eight or more by isoelectric focusing. A two-dimensional separation revealed 22 different polypeptide spots from the zein-1 and zein-2 fractions. A minor protein fraction, named reduced- soluble protein, was extracted with either the salt-soluble fraction or the total zein fraction, depending upon which solvent contained a reducing agent. The reduced-soluble protein has a unique amino acid composition with much more proline, histidine, cysteine, glycine, and valine and less aspartate, alanine, glutamic acid, and leucine than zein. It is, however, also very low in lysine.