Analysis of sialic acids in bovine intestinal mucins.

Molecular species of sialic acids released by mild acid hydrolysis from mucins of bovine small and large intestine were characterized by two dimensional thin-layer chromatography and gas chromatography-mass spectrometry. The small and large intestinal mucins contained both N-acetyl- and N-glycolylneuraminic acid. Although O-acetylated derivatives were not detectable in the small intestinal mucin, 9-O-acetyl-N-glycolylneuraminic acid was demonstrated in the large intestinal mucin by thin-layer chromatography and its structure was confirmed by mass spectrometry. Moreover, the presence of three kinds of O-acetyl-N-acetylneuraminic acid and five kinds of O-acetyl-N-glycolylneuraminic acid in the large intestinal mucin was suggested by thin-layer chromatography and mass chromatography. The limited distribution of O-acetylated neuraminic acids suggests that their derivatives are only produced in the mucous glands of the large intestine.