A A C C   2 0 0 0   A n n u a l   M e e t i n g

The use of capillary electrophoresis in the presence of sodium dodecyl sulfate (SDS-CE) for separation and quantification of HMW glutenin subunits was investigated. HMW glutenin subunits were precipitated with 40% acetone from 50% 1-propanol extract of flour under reducing conditions after removal of monomeric proteins with 50% 1-propanol. Poly (ethylene oxide) was used in the running buffer (3% w/v) for the SDS-CE. The results indicated that most of the HMW glutenin subunits could be clearly separated by the SDS-CE except HMW glutenin subunits 1 and 2*. HMW glutenin subunits showed delayed migration times compared to molecular weight protein standards. Some HMW glutenin subunits were reversed in their mobilities in SDS-CE compared to their mobility/molecular weights by SDS-PAGE. A linear response was obtained from SDS-CE of a plot of the concentration of HMW glutenin subunits of the 40% acetone precipitate vs corrected areas for absorbance at 214 nm. Quantification of HMW glutenin subunits for the two biotypes (subunits 5 + 10 vs 2 + 12) of an Australian wheat cultivar Warigal indicated that the biotype with subunits 5 + 10 had a greater proportion and quantity of the Glu-D1 HMW glutenin subunits than the biotype with 2 + 12 subunits. This quantitative difference in HMW subunit composition might be responsible for their differences in bread-making quality between the two biotypes. The technique could be used to confirm and quantify HMW glutenin subunits in conjunction with SDS-PAGE.