SIALYLATION AND SULFATION OF THE CARBOHYDRATE CHAINS IN RESPIRATORY MUCINS FROM A PATIENT WITH CYSTIC-FIBROSIS

Mucin glycopeptides were prepared from the sputum of a patient sufferi ng from cystic fibrosis. The carbohydrate chains were released by alka line borohydride treatment. Sialylated and sulfated oligosaccharide-al ditols were purified by ion-exchange chromatography, gel filtration, a nd high performance anion-exchange chromatography. The structures of t he oligosaccharide alditols were determined by high resolution H-1 NMR spectroscopy in combination with fast atom bombardment-mass spectrome try. Twenty-four oligosaccharides were characterized and illustrate th e diversity of the carbohydrate chains of cystic fibrosis respiratory mucins. Among these 24 oligosaccharide-alditols, 15 are novel structur es. Sialylation may occur on the C-6 of the N-acetylgalactosamine invo lved in the carbohydrate-peptide linkage or on a terminal galactose re sidue, either on C-3 or on C-6. Sulfation may occur either on the C-3 of a terminal galactose residue or on the C-6 of a N-acetylglucosamine residue. The most complex structures contain sulfated derivatives of the H, X, or Y determinants or a sialylated and sulfated derivative of the X determinant (Structure A).