The susceptibility of wheat glutenin to enzymatic hydrolysis has been examined to obtain information on structural properties of the glutenin molecule. Native glutenin was prepared under mild conditions to avoid denaturation of glutenin. The obtained glutenin was hydro-lyzed with trypsin, chymotrypsin, sobtilisin or pepsin. The extent of hydrolysis was analyzed by discontinuous sodium dodecyl sulfate(SDS)-polyacrylamide gel electrophoresis. Native glutenin was hydrolyzed at a very fast rate with the enzymes. All subunits of glutenin disappeared early in hydrolysis and no obvious difference was observed in the rate of hydrolysis among these subunits. The reduction of disulfide bonds of glutenin and the denaturation of glutenin by treatment with 8M urea, SDS or heating did not affect the hydrolysis profiles. The results suggest that glutenin may have an unfolded structure rather than a rigid structure and that subunits of native glutenin were exposed equally to the solvent.