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Donald D. Kasarda, Ph.D. Research Chemist (Retired)/Collaborator U.S. Department of Agriculture

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

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Donald D. Kasarda, Ph.D. Research Chemist (Retired)/Collaborator U.S. Department of Agriculture

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

  2. Diagram of a Wheat Kernel

  3. starch granule endosperm protein FLOUR PARTICLES

  4. Glutamine/Proline Composition of Wheat Prolamins (Mole Percent) Gln Pro Gln + Pro w gliadins 43-54 20-29 63-83 a, b, g gliadins + 36-42 15-19 51-61 LMW-glutenin subunits 12-27 42-55 30-38 HMW-glutenin subunits

  5. 2-Dimensional electrophoretic pattern of gluten proteins

  6. “Consensus” Repeat Types for Gluten Proteins -P-Q-Q-P-(Y/F)-P a-gliadins -Q-Q-P-Q-Q-P-F-P- g-gliadins -Q-P-Q-Q-P-F-P- D-type w-gliadins B-type w-gliadins -Q-Q-Q-F-P- LMW-glutenin subunits -Q-Q-Q-Q-P-P-F-S- -Q-Q-G-Y-Y-P-T-S-P- HMW-glutenin subnits

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

  8. *

  9. NIQVDPSGQVQWPQQQQPFPQPQQPFSQQPQQIFPQPQQ g-Gliadin sequence TFPHQPQQAFPQPQQTFPHQPQQQFPQPQQPQQPFPQQP g QQQFPQPQQPQQPFPQQPQQQFPQPQQPQQPFPQPQQPQ g LPFPQQPQQPFPQPQQQPQQPFPQLQQPQQPLPQPQQPQ g TTTVQYNPSEQYQPYPEQQEPFVQQQQPFVQQ Av Avenin Sequence QQPFPQQQQPLIQPYLQQQMNPCKNYLLQQCNPVSLVSSL g QQPFVQQQQMFLQPLLQQQLNPCKQFLVQQCSPVAAVPFL Av VSMILPRSDCKVMRQQCCQQLARIPQQLQCAAIHGIVHSI g RSQILRGAICQVTRQQCCRQLAQIPEQLRCPAIHSVVQSI Av IMQQEQQQQQQQQQQQQQGIQIMRPLFQQQQVGQGILVQG g ILQQQQQQQQFIQPQLQQQVFQPQLQLQQQVFQPQMQ--- Av --------------IIQPQQPAGLEVIRSLVLGTLPTMCN g QLQQQVFQPQLQQVFNQPQMAGQIEGMRAFALQALPAMCD Av VFVPPECSTTKAPFASIVADIGGQ VYVPPQCPVATAPLGGF (Avenins make up ~10% of oat proteins)

  10. Currently Favored Analytical Method for Gluten in Food R-5 monoclonal antibody ELISA test is available commercially. Antibody reacts with monomeric wheat, rye, and barley prolamins, but not oat avenins; reacts weakly or not at all with glutelins (glutenin). Detection down to about 1.5 parts per million; quantification above 2.5 parts per million has been reported. RecognizesQQPFP and LQPFP motifs most strongly. 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.

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