131 A comparison of polymers for SDS-CE separations of wheat proteins.

S. R. BEAN (1) and G. L. Lookhart (2). (1) Dept. of Grain Science & Industry, Kansas State Univ., Manhattan, KS 66506; (2) USDA, ARS, GMPRC, Manhattan, KS 66506.

Non-cross linked polyacrylamide (PAA), polydimethyl acrylamide (PDMA), dextran, polyethylene oxide (PEO), polyvinyl alcohol (PVA), and a commercial polymer from BioRad were evaluated for use in SDS-capillary electrophoresis (CE) separations of wheat proteins. Each polymer was optimized (where possible) by manipulating polymer concentration, buffer (pH, ion type), concentration, and through the use of organic modifiers (methanol and ethylene glycol [EG]). The addition of 15% EG to the separation buffer was found to generally improve the resolution of the separations, except for some polymers such as PEO. The addition of EG was necessary to resolve several pairs of HMW-GS, such as 1 and 5. Several HMW-GS showed migration patterns different from those typically seen in SDS-PAGE (e.g. 1 & 5). Once optimized, all polymers provided good separations of wheat proteins, though each had particular advantages and disadvantages. In addition, the molecular weights of the wheat proteins predicted by the various buffer systems differed from each other and the predicted cDNA mass. Separations done with a commercial polymer from BioRad modified by the addition of EG showed high resolution separations of both high molecular weight and low molecular weight glutenins. Good repeatability was found with this method for both migration time (<1% RSD) and corrected peak area (~1%).