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Action of glutaraldehyde, nitrous acid or chlorine on wheat proteins
Author(s) -
Ewart J. A. D.
Publication year - 1968
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740190704
Subject(s) - cysteic acid , chemistry , lysine , deamination , tryptophan , biochemistry , tyrosine , gliadin , histidine , nitrous acid , cystine , performic acid , bran , amino acid , pronase , glyoxal , methionine , gluten , organic chemistry , cysteine , trypsin , enzyme , raw material
The amino acid analyser has been used to determine which amino acid side chains (except that of tryptophan) in wheat proteins are attacked by three reagents. Glutaraldehyde crosslinks gliadin by reacting with lysine and tyrosine residues so that it gives an electrophoretic pattern resembling that of glutenin. Wheat gliadin after treatment with nitrous acid suffers an overall reduction in electrophoretic mobility due to deamination of lysine side chains. Chlorine oxidises part of the cystine and methionine of wheat flour protein to cysteic acid and the sulphone respectively, destroys a fraction of the tyrosine and histidine, and causes some deamidation probably as a result of hydrolysis by hydrochloric acid. The results suggest that there may be buried lysine and tyrosine residues in, and some degrees of structural similarity among, the gliadin proteins. Additional support for the crosslinked nature of glutenin is provided.