Cereal Chem 48:677 - 689.  |  VIEW ARTICLE
Differences in Amino Acid Sequences of Gliadin and Glutenin.

J. A. Bietz and J. A. Rothfus. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

Gliadin and glutenin were examined to identify peptides that differentiate the proteins. Pronase-resistant fragments from gliadin and glutenin have average molecular weights of 460 and 640, respectively, and in acid are readily converted to pyroglutamic acid (PGA) peptides. PGA-peptides isolated from pepsin- hydrolyzed Pronase digests contained glutamine (Gln) or glutamic acid; proline, serine, and glycine were other common residues. Several peptides were common to digests of both proteins; but most were unique, demonstrating sequence differences between gliadin and glutenin. Yield data suggested that most unique peptides were from a single protein or only a few different ones. Glycine occurs more frequently in the PGA-peptides from glutenin; and proline, in those from gliadin. That Gln is also positioned differently in the two proteins was evidenced by the enzymatic release of more PGA from glutenin than from gliadin and more PGA-Gln and PGA-Gln-Gln from gliadin than from glutenin.