Glutenin dispersed in 0.2 M sodium phosphate buffer (pH 7.0) was heated at various temperatures for 15 min. Effects of the heat-treatment on the subunit pattern was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). No change in the subunit pattern of glutenin was observed by heating at 120℃. A high molecular weight protein which did not migrate into gel matrix during electrophoresis was observed in the glutenin heat-treated at a temperature higher than 130℃. All the subunits disappeared by heating at 150℃. Increasing the temperature elevated the ratio of soluble fractions in 7.5% trichloroacetic acid (TCA-soluble fraction), and about 50% of glutenin changed into TCA-soluble fractions by heating at 170℃. These results suggest that polymerization and decomposition of glutenin subunits occurred simultaneously by heating at high temperatures. (accepted. Oct. 30, 2009)