Two-Dimensional Gel Mapping and N-Terminal Sequencing of LMW-Glutenin Subunits

Low-molecular-weight glutenin subunits from the wheat (Triticum aestivum L.) cultivar 'Chinese Spring' were mapped using two dimensional electrophoresis (isoelectric focusing versus SDS-polyacrylamide gel electrophoresis). Protein spots were electroblotted on to polyvinylidene difluoride membrane and characterized by N-terminal amino acid sequencing. Most of the proteins that had accessible N-termini gave sequences in agreement with known sequences for low-molecular-weight glutenins, a-type gliadins, and y-type gliadins. Two variants which have not been seen in direct sequencing before were found. The glutenin starting material was also reduced, alkylated, and partially fractionated by reverse-phase high performance liquid chromatography. Sequencing of these fractions, each of which contained a mixture of proteins, confirmed the presence of the glutenin variants found in the spot sequencing.