Cereal Chem 68:276-279   |  VIEW ARTICLE

Quantitation and Distribution of Gamma-Zein in the Endosperm of Maize Kernels.

E. Paiva, A. L. Kriz, M. J. V. V. D. Peixoto, J. C. Wallace, and B. A. Larkins. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Changes in the content of gamma-zein (Mr 27,000) in the endosperm of normal, opaque-2, floury-2, and modified opaque-2 maize varieties known as quality protein maize (QPM) were evaluated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, protein fractionation schemes, and an immunoabsorbance assay. QPM genotypes, which combine high levels of lysine and tryptophan with high yields, traditional appearance, and conventional kernel hardness, were shown to contain two to five times more gamma-zein than normal, opaque-2, or floury-2 genotypes. Both soft and hard regions of QPM endosperm are enriched in gamma-zein; the latter show higher levels of alpha-zeins. Relationships between amounts of zeins, kernel hardness, nutritional quality, and changes in other major protein components are discussed.