Cereal Chem 46:253 - 262.  |  VIEW ARTICLE
Distribution and Subcellular Structure of Endosperm Protein in Varieties of Ordinary and High- Lysine Maize.

M. J. Wolf, U. Khoo, and H. L. Seckinger. Copyright 1969 by the American Association of Cereal Chemists, Inc. 

All varieties of corn show a high protein content in the peripheral endosperm beneath the aleurone layer, and a decreasing gradient of protein concentration from the periphery inward. In addition to the common starchy types of endosperm cell, small amounts of two kinds of high-protein cells containing little or no starch were noted: (a) high-protein cells scattered at random among starchy cells are common in floury mutants, floury-1 and opaque-1; (b) special high-protein cells occur only in the subaleurone area, usually as a fragmentary layer.Subcellular protein bodies soluble in ethanol, dimethyl sulfoxide, and acetone are characteristic of the protein structure in endosperm of all normal maize. The bodies, ranging from 1.4 to 1.8 micron in average diameter in normal corn, were absent at the light microscope level only in the high-lysine mutants, floury-2 and opaque-2; small protein granules, about 0.1 micron in diameter, were found by electron microscopy in opaque-2 but not in floury-2. Demonstration of subcellular, alcohol-soluble protein bodies in endosperm cells by light microscopy provides a reliable indication that the protein composition of the variety is normal. Conversely, inability to detect alcohol-soluble protein granules indicates that the protein present is high in lysine.