CHARACTERIZATION OF OLIGOSACCHARIDES FROM THE NONREDUCING TERMINI OF KERATAN SULFATE CHAINS

Keratan sulphate (KS) chains prepared from both bovine tracheal rings and bovine femoral head cartilage were digested with the enzyme keratanase from Pseudomonas species and non-reducing terminal oligosaccharides were fractionated and purified using high-performance ion-exchange chromatography. Two oligosaccharides were fully characterized using one- and two-dimensional NMR spectroscopic methods. An oligosaccharide derived from bovine tracheal ring KS chains was shown to have the structure NeuAcalpha2-3Galbeta1-4GlcNAc(6-SO4)beta1-3 Gal(6-SO4)beta1-4GlcNAc(6-SO4)beta1-3Gal-ol (1). An oligosaccharide derived from bovine articular cartilage after treatment with a keratanase preparation containing neuraminidase activity was shown to have the structure Galbeta1-4GlcNAc(6-SO4)beta1-3Gal(6-SO4)beta1-4GlcNAc(6-SO4)beta1-3Gal-ol (2). These non-reducing terminal structures are KS chain caps or terminators which, because of their accessibility, are likely to be involved in interactions with other macromolecules of the extracellular matrix.