No abstract

A peptidomics approach was developed to identify transglutaminase-susceptible Q residues within a pepsin^trypsin gliadin digest. Based on tagging with a monodansylcadaverine £uorescent probe, six K K/L L-, Q Q-gliadin, and low molecular weight glutenin peptides were identi¢ed by nanospray tandem mass spectrometry. In functioning as an acyl acceptor, tissue transglutaminase was able to form complexes with the glutamine-rich gliadin peptides, whereas by lowering pH, the peptides were deamidated by transglutaminase at the same Q residues, which were previously transamidated. The main common feature shared by the peptides was the consensus sequence Q-X-P. Our ¢ndings o¡er relevant information for the understanding of how dietary peptides interact with the host organism in celiac disease.

Developing seeds from Triticum aestivum (wheat) cultivars were collected after flowering and analysed for puroindoline a and b gene expression by Real Time RT-PCR. Mature seeds were investigated for the presence and the amount of starch-associated puroindoline a and b proteins by flow cytometry. Puroindoline a gene and protein were found to have a predominant role in controlling wheat kernel hardness.

Natural L-homocysteine and L,L-cystathionine, along with a series of unnatural analogues, have been prepared from L-aspartic and L-glutamic acid. Manipulation of the protected derivatives provided ω-iodoamino acids, which were used in thioalkylation reactions of sulfur nucleophiles, such as the ester of L-cysteine and potassium thioacetate.