Cereal Chem. 70:602-606   |  VIEW ARTICLE

Evidence for Glycosylation of the High Molecular Weight Glutenin Subunits 2, 7, 8, and 12 from Chinese Spring and TAM 105 Wheats.

K. A. Tilley, G. L. Lookhart, R. C. Hoseney, and T. P. Mawhinney. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

High molecular weight glutenin subunits (HMW-GS) of wheat, obtained by a modification of the method of Burnouf and Bietz (1989), were characterized by isoelectric focusing, lectin binding, and gas chromatography-mass spectroscopy. The purification method involved a dimethyl sulfoxide extraction of flour, followed by reduction and alkylation of the proteins. The extracted subunits were separated on, and excised from, sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. These subunits, when analyzed by reversed phase high-performance liquid chromatography, eluted at approximately 45% acetonitrile, indicating that, under these conditions, they were more hydrophobic (approximately 30%) than previously reported (Burnouf and Bietz 1989, Wieser and Belitz 1990). The purified HMW-GS were reelectroporesed on sodium dodecyl sulfate polyacrylamide gel electrophoresis minigels and silver-stained. A single band for each subunit provided an indication of the purity of the subunit. Further characterization of the purified HMW-GS revealed that the proteins were glycosylated. Lectin-binding analyses showed that the terminal carbohydrate moiety of these glycoproteins was mannose. Gas chromatography-mass spectroscopy analyses confirmed the presence of mannose in the total glutenin preparati ons as well as in each of the individual purified HMW-GS. Gas chromatography-mass spectroscopy analyses also detected glucose and N-acetyl glucosamine in the individual purified HMW-GS.