Separation and quantification of HMW glutenin subunits by capillary electrophoresis

The use of capillary electrophoresis in SDS (SDS-CE) for separation and qua ntification of HMW glutenin subunits (HMW-GS) was investigated. HMW-GS were precipitated with 40% acetone from 50% 1-propanol extract of flour under r educing conditions after removal of monomeric proteins with 50% 1-propanol. Poly (ethylene oxide) was used in the running buffer (3% w/v) for SDS-CE. The results indicated that HMW-GS could be well separated by SDS-CE, includ ing subunits 7+8, 7+9, 2+12, 5+10, and 17+18. However, HMW-GS showed delaye d migration times compared with molecular weight protein standards. Some HM W-GS were reversed in their mobilities in SDS-CE compared with their mobili ty and molecular weights by SDS-PAGE Therefore, the SDS-CE was unsuitable f or MW determination of HMW-GS. A linear response was obtained from SDS-CE o f a plot of the concentration of HMW-GS of the 40% acetone precipitate vers us corrected areas for absorbance at 214 mn. Quantification of HMW-GS for t he two biotypes (subunits 5+10 vs., 2+12) of an Australian wheat cultivar W arigal confirmed the differences between the two biotypes in their quantity of HMW-GS. Therefore, the technique could be used to quantify HMW-GS in co njunction with SDS-PAGE.