POLYMERIC GLUTENIN OF WHEAT LINES WITH VARYING NUMBER OF HIGH-MOLECULAR-WEIGHT GLUTENIN SUBUNITS

Glutenin of wheat lines that were null for some or all of the high mol ecular weight (HMW) subunits was extracted with urea-sodium dodecyl su lfate (SDS) solvent from the Osborne glutenin (ethanol-insoluble) frac tion. For the eight lines examined, the amount of glutenin protein ran ged from 32 to 55% of the flour protein. The line with no HMW subunits had the lowest amount of glutenin, while the line with all five of th e HMW subunits had the highest amount. The glutenin, dissolved in urea -SDS, was fractionated by gel filtration on Sephacryl S-500 using the same solvent as the eluent. Gel-filtration fractions were collected, p artially purified by ultrafiltration and dialysis, and analyzed by SDS -polyacrylamide gel electrophoresis (PAGE). Gel-filtration results sho wed that there was little difference in the glutenin elution profile f or the different wheat lines. The elution profile for the line that co ntained no HMW glutenin subunits was essentially the same as that for the control that contained all five of the HMW glutenin subunits. Thes e results indicate that the low molecular weight (LMW) glutenin subuni ts by themselves can form glutenin polymers that appear to be similar in molecular size to the polymers containing both the HMW and the LMW subunits. These results suggest that the contribution of glutenin to i ntervarietal differences in bread-making quality in the eight wheat li nes examined depends on properties other than the differences in molec ular weight distribution.