Regional differences in sulfated oligosaccharides of rat gastrointestinal mucin as detected by two-dimensional chromatography.

Radiolabeled sulfated mucin was obtained from rat gastrointestinal tract tissue (corpus, antrum, duodenum, jejunum, ileum, or colon) incubated with [35S]sulfate in vitro by fractionation of extracts on Superose 6 followed by purification with CsCl density gradient centrifugation. Significant amounts of 35S-labeled mucin were obtained from each tissue and radioactivity differed according to region, in the order colon > duodenum > jejunum > corpus > antrum > ileum. Gel-permeation chromatography of 35S-labeled oligosaccharides liberated from each mucin by alkaline-borohydrate treatment indicated the 35S-labeled oligosaccharides of each mucin differ with respect to elution position. Further examination of fractions eluted from the gel-permeation column by thin-layer chromatography showed region-specific chromatograms for the sulfated oligosaccharides. Thus, not only the degree of sulfate incorporation but sulfated oligosaccharide structure differs according to the region in gastrointestinal mucin.