Comparative study of carbohydrate portion of gastrointestinal mucins using enzyme-linked lectin-binding assay (ELLA)

We improved the enzyme-linked lectin-binding assay (ELLA) to determine the differences in the carbohydrate chains of corpus, antral, duodenal ant colonic rat mucins. First we have improved the optimal conditions of this assay for mucins; ELLA makes possible the detection of 1.5 ng of hexose in rat gastrointestinal mucins (5-7 ng of mucins). Salt concentrations of several dozens mM are required for mucin coating on the plate. Non-ionic detergents diminish the adsorption of mucins onto the plate. Secondly we tested a set of 8 lectins to compare their binding to the gastrointestinal mucin samples. It is possible to detect crude mucins as well as purified mucins using ELLA. Gastric mucins have less Tn-antigen than duodenal and colonic mucins. Corpus and duodenal mucins have more of the H-type 2 chain than antral and colonic mucins.