Cereal Chem. 70:689-695   |  VIEW ARTICLE

Albumin Fraction from Spring, Winter, and Soft Wheats---Protein and Associated Carbohydrate Identified by Gel Filtration Chromatography and Gel Electrophoresis.

J. D. C. Figueroa and K. Khan. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Wheat flour proteins are a mixture of albumins, globulins, gliadins, and glutenins. The carbohydrates associated with some of the proteins of each class may be useful indicators of wheat quality. Therefore, the albumins of two hard red spring, one hard red winter, and two soft red winter wheats were fractionated by gel filtration chromatography in a solvent of 0.1M acetic acid and 8M urea on Sephacryl S-300 for characterization of protein and associated carbohydrate. Proteins eluted in peaks I, II, and III; carbohydrates eluted in peaks I, II, and IV. The quantity of the carbohydrates in peak I of albumin proteins was highest in the hard red spring wheats (Butte and Era) and lowest in the soft red winter wheats (Fairfield and Titan). The albumin proteins of peak II of soft red winter wheat seem to be associated with high levels of sugar. Peak III, a low molecular weight albumin subfraction, and peak IV, a low molecular weight carbohydrate fraction, do not seem to be associated with sugar or nitrogen material, respectively. Analysis of total albumin, and those fractions from gel filtration by urea-polyacrylamide gel electrophoresis using periodic acid-Schiff staining for carbohydrates and Coomassie Brilliant Blue staining for proteins, showed that the carbohydrate components were associated with the high molecular weight polypeptides. During gel filtration, protein and carbohydrate eluted in peaks I and II, and protein and carbohydrate comigrated on urea-polyacrylamide gel electrophoresis, which indicate that protein in those peaks may be covalently linked to carbohydrate.