Donald D. Kasarda, Ph.D. Research Chemist (Retired)/Collaborator U.S. Department of Agriculture Agricultural Research Service Western Regional Research Center Albany, California Gluten Proteins in Relation to Celiac Disease

Diagram of a Wheat Kernel

FLOUR PARTICLES starch granule endosperm protein

Glutamine/Proline Composition of Wheat Prolamins (Mole Percent)  gliadins  gliadins LMW-glutenin subunits HMW-glutenin subunits GlnProGln + Pro

2-Dimensional electrophoretic pattern of gluten proteins

“Consensus” Repeat Types for Gluten Proteins -P-Q-Q-P-(Y/F)-P  -gliadins  -gliadins -Q-Q-P-Q-Q-P-F-P- D-type  - gliadins B-type  - gliadins -Q-Q-Q-F-P- -Q-P-Q-Q-P-F-P- LMW-glutenin subunits HMW-glutenin subnits -Q-Q-Q-Q-P-P-F-S- -Q-Q-G-Y-Y-P-T-S-P-

Leu Gly Gln Pro Tyr Phe Molecular model of a 13-residue gliadin peptide (a 13-mer) FL-G-Q-Q-Q-P-F-P-P-Q-Q-P-YFL-G-Q-Q-Q-P-F-P-P-Q-Q-P-Y

Currently Favored Analytical Method for Gluten in Food R-5 monoclonal antibody ELISA test is available commercially. Detection down to about 1.5 parts per million; quantification above 2.5 parts per million has been reported. Antibody reacts with monomeric wheat, rye, and barley prolamins, but not oat avenins; reacts weakly or not at all with glutelins (glutenin). The Codex Alimentarius Committee on Methods agreed in 2004 to endorse temporarily the R5 ELISA for the determination of gluten. Possible problems: failure to detect glutelin (glutenin) proteins and small peptides from hydrolysates. Recognizes QQPFP and LQPFP motifs most strongly.