OLIGOSACCHARIDES DERIVED BY ENDO-BETA-GALACTOSIDASE DIGESTION OF BOVINE CORNEAL KERATAN SULFATE - CHARACTERIZATION OF TETRASACCHARIDES WITHINCOMPLETE SULFATION AND CONTAINING UNSULFATED N-ACETYLGLUCOSAMINE RESIDUES

Bovine corneal keratan sulphate has been fragmented using the enzyme e ndo-beta-galactosidase and H-1-NMR chemical shift data are reported fo r live newly isolated tetrasaccharides which derived from the repeat r egion. They have the structures: GlcNAc(beta 1-3)Gal(beta 1-4)GlcNAc6S (beta 1-3)Gal-ol, GlcNAc6S(beta 1-3)Gal(beta 1-4)GlcNAc(beta 1-3)Gal-o l, GlcNAc(beta 1-3)Gal6S beta(1-4)GlcNAc6S(beta 1-3)Gal-ol, GlcNAc6S(b eta 1-3)Gal6S(beta 1-4)GlcNAc(beta 1-3)Gal-ol, and GlcNAc6S(beta 1-3)G al(beta 1-4)GlcNAc6S(beta 1-3)Gal-ol. Structures for two trisaccharide s formed by a peeling reaction are also given. These are GlcNAc(beta 1 -3)Gal6S(beta 1-4)GlcNAc-ol and GlcNAc6S(beta 1-3)Gal(beta 1-4)GlcNAc6 S-ol where GlcNAc6S-ol represents N-acetylglucosaminitol 6-O-sulphate. Characterisation of such structures and their spectral assignments wi ll be of considerable value for the studies of both selectin ligands a nd undersulphated keratan sulphates such as those occurring on cell su rfaces and in brain tissue.