Coeliac Disease

Coeliac Disease:Gliadin is a Good Substrate of Several Transglutaminases: Possible Implication in the Pathogenesis of Coeliac Disease.

By: Sjöström, H.. Scandinavian

Journal of Gastroenterology,

Jul 2002, Vol. 37 Issue 7, p812, 6p;

Abstract:

Background: Deamidation of distinct glutamines in HLA-DQ2 restricted gliadin epitopes, considered critical in the pathogenesis of coeliac disease (CD), can be mediated by tissue transglutaminase (tTG). To elucidate the possible role of other transglutaminase s in CD we investigated whether different mammalian, microbial and vegetable transglutaminases can use gliadin as substrate.

Methods: Studies in which small amounts of transglutaminase have been measured have led to our modifying a microtitre plate assay. We used proteolytically digested gliadin as solid phase substrate and Europium-labelled streptavidine to quantify the biotinylated product covalently linked by the enzyme to the plate.

Results: The modified assay is ultrasensitive and quantitative, measuring guinea pig liver transglutaminase concentrations between 0.5 and 50 ng/well. The specific activities of the enzymes (counts/min/mg) against gliadin and N,N-dimethylcasein, respectively, are: tTG 9800/4900, Factor XIII 97330/55620, epidermal transglutaminase 47650/50770, streptoverticillium transglutaminase 4290/2200, phytophora cactorum transglutaminase 6910/4110. For the first time, we have detected transglutaminase activity in bean sprouts, spinach leaves and green peas, which are commonly used vegetables.

Conclusion: Gliadin is a good substrate for endogenous, microbial and plant transglutaminases. An interesting alternative is that gliadins are deamidated by microbial or food transglutaminase s in the intestinal lumen. The assay described provides an ultrasensitive method for measuring small amounts of transglutaminase and is considered a helpful tool in further studies of the possible role of transglutaminases in the pathogenesis of CD