Mucus glycoproteins (mucins) were extracted from the duodenum, small intestine (proximal and distal parts) and colon. 2. Enteromucin subunits were larger than 2 x 10(6). 3. The glycopeptides of enteromucins were essentially the same in size of the subunit. 4. The carbohydrate portion of enteromucins consisted of N-acetylgalactosamine, N-acetylglucosamine, galactose, fucose and sialic acid and the ratios of these sugars differed according to the region. 5. Average oligosaccharide length was about 8, 8, 8 and 14 sugars in the duodenum, proximal small intestine, distal small intestine and colon, respectively. 6. The proportion of threonine to serine in small intestinal mucins differed from duodenal and colonic mucins. Duodenal and colonic mucins were richer in threonine than small intestinal mucins. 7. Proximal and distal small intestinal mucins showed the same features. 8. A comparison of rat enteromucins to gastromucins indicated enteromucins to have large subunits and glycopeptides. The threonine and sialic acid content of enteromucins was higher and fucose content less compared to gastromucins.
