Cereal Chem 43:119 - 126. | VIEW
Optical Rotatory Dispersion of Wheat Gluten, Gliadin, and Glutenin in Acetic Acid and Aluminum Lactate Systems.
J. E. Cluskey and Y. V. Wu. Copyright 1966 by the American Association of Cereal Chemists, Inc.
The conformations of gluten, gliadin, and glutenin were studied by optical rotatory dispersion in 0.01N acetic acid and also in 0.008M aluminum lactate-lactic acid buffer, pH 3.1, micron = 0.05, with and without 3M urea. The wave-length range covered was from 600 to around 220 millimicrons or lower. All three proteins in each solvent exhibited a negative Cotton effect at 233 millimicrons (specific rotation ranging from -3,900 degrees to -6,300 degrees). Values of b0 from Moffitt-Yang plots were interpreted by the conventional method (b0 = -630 for 100 % right-handed alpha-helix). The optical rotatory dispersion data were also treated by a modified two-term Drude equation of Shechter and Blout. Results indicate that gliadin contains more alpha-helix than glutenin and whole gluten. The amount of alpha-helix in a given protein is the same in acetic acid and aluminum lactate. With inclusion of 3M urea in the aluminum lactate buffer, the helix content decreases slightly for each protein. Glutenin and gliadin in acetic acid and in aluminum lactate probably are mixtures of random coil and helix. These results supplement those reported earlier by Wu and Cluskey using different solvent systems.