Cereal Chem 51:240 - 249. | VIEW
Wheat Glutenin Subunits. II. Compositional Differences.
F. R. Huebner, G. L. Donaldson, and J. S. Wall. Copyright 1974 by the American Association of Cereal Chemists, Inc.
Isolation of subunits from reduced wheat glutenin protein by new procedures has permitted detailed chemical and physical studies of them. The subunits were separated from S-pyridylethyl derivatives of reduced glutenin by gel filtration into three distinct groups (A, B, and C) which were resolved further by ion-exchange chromatography. Toluenesulfonic acid hydrolysates of the isolated subunits were analyzed for amino acids by modified techniques of automated ion-exchange chromatography. Proteins from fraction A contained considerably more basic amino acids, as well as aspartic acid, than proteins in fractions B and C. Much lower amounts of glutamic acid and proline were present in fraction A proteins than either the B and C fraction or gliadin proteins. Some protein from group B contained the highest amount of glycine--almost six times more than either fraction C or the gliadins. Also, fraction B proteins were lower in valine, isoleucine, and phenylalanine than either A or C proteins. Fraction C proteins resemble gliadins in amino acid composition, except for a slightly higher content of cysteine. Aspartic and glutamic acids were major N-terminal groups of glutenin subunits from all fractions.