['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 transglutaminases in CD we investigated whether different mammalian, microbial and vegetable transglutaminases can use gliadin as substrate.', '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.', '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.'] Is gliadin a good substrate of several transglutaminases : possible implication in the pathogenesis of coeliac disease?