The mucus of the duodenal fluid of children contains a mixture of carbohydrateprotein complexes with the character of mucoids and glycoproteins. In duodenal fluids from patients with cystic fibrosis of the pancreas about one-third in controls about 90%, of the mucoid material is soluble in trichloroacetic acid (TCA). In duodenal fluids from patients with cystic fibrosis about one-third of the mucoid becomes denatured and insoluble in water when precipitated with an ethanolbenzene mixture. The TCA-soluble mucoid from patients with cystic fibrosis and controls was separated by fractionated ethanol precipitation into four fractions: three precipitating at 50% (A); 67% (B); and 90% (C), respectively; and one soluble in 90% ethanol. All four fractions contain as carbohydrate moiety a fucomucopolysaccharide. Fractions C and D contain about equivalent amounts of galactose and mannose and in patients with cystic fibrosis only one hexosamine (glucosamine) in demonstrable amounts. Fractions A and B contain glucosamine as well as galactosamine in comparable amounts, but the hexose present is galactose to an extent of more than 80%. The polysaccharides of all four mucoid fractions differ in their content of sialic acid. The least-soluble fraction A contains less of it than the more soluble fractions. The content of sialic acid in the mucopolysaccharide of the water-insoluble mucoid, and of the TCA-insoluble water-soluble fraction from pooled duodenal fluids of patients with cystic fibrosis, approaches that of fraction A and is lower than that of other fractions. The molar ratio of fucose to hexosamine in fraction A, and in the water-insoluble mucoid from patients with cystic fibrosis, is higher than in all fractions from controls.
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Dische et al. (1959) studied this question.