Regional differences in pig gastric mucins.

1. Mucus glycoproteins (mucins) were extracted from cardiac, fundic and pyloric regions of pig stomach. 2. The cardiac and pyloric regions were richer with mucins than the fundic region. 3. Threonine and proline content decreased in the order of cardiac, fundic and pyloric mucin. That of serine increased in the order of cardiac, fundic and pyloric mucins. 4. The carbohydrate of gastric mucins consisted of N-acetylgalactosamine, N-acetylglucosamine, galactose and fucose. The ratios of carbohydrate composition among cardiac, fundic and pyloric mucins differed. 5. Average oligosaccharide length was about 14-15, 12-13 and nine sugars in cardiac, fundic and pyloric mucins, respectively. 6. Disulfide bond reduction of mucins with dithiothreitol led to the production of a larger (M(r) about 8.8 x 10(7)) and a smaller subunit (M(r) about 1.2 x 10(6)). Their ratio differed for each of the three regions. The proportion of the larger subunit decreased in the order of cardiac, fundic and pyloric mucins, as 100, 61.4 and 44.8%, respectively.