title: New Methods for Extraction and Quantitation of Zeins Reveal a High Content of gamma-Zein in Modified opaque-2 Maize.
abstract: We have developed methods for quantitative extraction and analysis of zeins from maize (Zea mays L.) flour. Extraction involved solubilization of total endosperm proteins in an alkaline buffer containing SDS and 2-mercaptoethanol with subsequent precipitation of nonzein proteins by the addition of ethanol to 70%. Analysis of these proteins by SDS-PAGE with Coomassie blue staining and by Western blotting and ELISA assay with zein antibodies revealed that this extraction method is more quantitative than the traditional Landry-Moureaux procedure, especially for the beta- and gamma-zeins. This method was used to extract and analyze the zein content of several ;Quality Protein Maize' (QPM) varieties developed by the International Maize and Wheat Improvement Center. QPM varieties contain ;modifier genes' that confer a vitreous phenotype on opaque-2 genotypes, while maintaining the elevated levels of lysine and tryptophan characteristic of this mutant. This analysis revealed that the QPM types contain 2 to 4 times the amount of the gamma-zein than unmodified opaque-2 or normal maize varieties. Possible relationships between the high expression of the gamma-zein and the modified opaque phenotype are discussed.
authors: Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907.
authors: J C
authors: JC
authors: Wallace
authors: M A
authors: MA
authors: Lopes
authors: E
authors: E
authors: Paiva
authors: B A
authors: BA
authors: Larkins