Cereal Chem 48:336 - 350.  |  VIEW ARTICLE
Changes in the Protein Fractions of Developing Normal and opaque-2 Maize Endosperm.

J. J. Murphy and A. Dalby. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

The proteins of the endosperm of a normal inbred line of maize (W64A) and its homozygous opaque-2 (o2) counterpart, sampled at intervals after pollination, were fractionated by a modified Osborne procedure, and selected fractions were subjected to amino acid analysis and starch-gel electrophoresis. The o2 gene causes a decrease in zein and an increase in glutelin, thus producing the higher lysine content characteristic of o2 endosperm. The amino acid composition of the zein isolated from o2 15 days after pollination is quite unlike that of the same fraction from 15-day normal or from o2 at later stages of development. The pattern of zein accumulation in o2 is consistent with the suggestion that the o2 gene is active only during the first 2 to 3 weeks after pollination in the maize inbred W64A. An increase in the amount of saline-soluble nitrogen in o2 is largely attributable to an increase in nonprotein nitrogen, notably glutamic acid, aspartic acid, and alanine.