Peptide mapping of IEF zein components from maize

Abstract Zein, the major storage protein of maize endosperm, was fractionated in several components by isoelectric focusing (IEF) and SDS electrophoresis. The peptide maps of tryptic-chymotryptic digests of zeins extracted from endosperms of OH 43 and B 73 inbreds differ in the number and location of spots. Thin-layer chromatography of the tryptic-chymotryptic digests of the 10 major IEF bands from OH 43 zein differ from each other. Finally, the peptide maps of three unique (by IEF + SDS-PAGE) bands from OH 43 zein also differ to some extent. We conclude that zein is a mixture of similar but not identical polypeptides and hence that the IEF zein components are probably the products of a set of structural genes.