Cereal Chem 48:601 - 608.  |  VIEW ARTICLE
Apolar Interactions of Alpha-Gliadin: Binding of 2-p-Toluidinylnaphthalene-6-Sulfonate.

F. C. Greene and D. D. Kasarda. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

The interactions of the wheat prolamine alpha-gliadin with 2-p-toluidinylnaphthalene-6-sulfonate (TNS) have been studied by fluorescence spectrophotometry and equilibrium dialysis. The fluorescence of TNS is enhanced in the presence of alpha-gliadin and the fluorescence yield of the protein.TNS couple is directly related to the extent of TNS binding as determined by equilibrium dialysis. Alpha-gliadin can bind appreciable amounts of TNS. The binding is interpreted as evidence of accessible apolar regions on the surface of the protein molecule. TNS binding is stronger at pH 3.1 than pH 5.0. This pH sensitivity may be related to conformational change in alpha-gliadin. An increase in the degree of protein aggregation may accompany the binding of TNS, probably as a result of partial neutralization of positive charges on the protein.