Cereal Chem 60:242 - 245.  |  VIEW ARTICLE
Polymorphism of Native Zein as Detected by Gel Filtration and Electrophoresis in the Presence or Absence of Sodium Dodecyl Sulfate.

J. Landry and M. Sallantin. Copyright 1983 by the American Association of Cereal Chemists, Inc. 

Unreduced zein, isolated by extracting maize grains with aqueous isopropyl alcohol and subjected to sodium dodecyl sulfate (SDS) polyacrylamide electrophoresis, is composed of several bands with mean molecular weight (mol wt) of 45,000 and two bands of 24,000 and 22,000 mol wt. When subjected to gel filtration on Ultrogel Ac44 in 1.5% SDS, zein was resolved into two main fractions. The first fraction consisted mostly of proteins with mol wt near 45,000. The second fraction contained a small amount of protein in 45,000 mol wt that eluted early, but consisted mostly of 24,000 mol wt protein that also eluted early, and 22,000 mol wt protein. When reduced, the two gel fractions contained only 24,000 and 22,000 mol wt components, but the percentage of 24,000 mol wt component was higher in the first than in the second fraction. The 24,000 and 22,000 mol wt components exhibited the same heterogeneity as detected in zein by starch gel electrophoresis in 6M urea at pH 3.5. These results show that unresolved zein is composed of several subunits displaying discrete variations in primary structure, and that it is able to exist as monomers or to associate into dimeric forms.