A non-reducing terminal fragment from tracheal cartilage keratan sulphate chains contains α(2-3)-linked N-acetylneuraminic acid

• Published in: Biochemical journal 1991-09, Vol.278 (3), p.779-785
• Main Authors: DICKENSON, J. M, HUCKERBY, T. N, NIEDUSZYNSKI, I. A
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; beta-Galactosidase - metabolism; Biological and medical sciences; Carbohydrate Conformation; Carbohydrate Sequence; Cartilage - chemistry; Cattle; Chromatography, Ion Exchange; Fundamental and applied biological sciences. Psychology; Glycoproteins; Glycoside Hydrolases; Keratan Sulfate - chemistry; Keratan Sulfate - metabolism; Magnetic Resonance Spectroscopy; Molecular Sequence Data; N-Acetylneuraminic Acid; Papain - metabolism; Proteins; Sialic Acids - analysis; Sialic Acids - chemistry; Trachea - chemistry
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/bj2780779

Keratan sulphate chains were isolated from bovine tracheal ring cartilage (15-18-month-old animals) after papain digestion of the tissue followed by ethanol fractionation, chondroitinase ABC digestion and alkaline borohydride reduction. The keratan sulphate chains were further purified by anion-exchange chromatography on a Pharmacia Mono-Q column in order to remove any contaminating chondroitin sulphate and O-linked oligosaccharides. The chains were then treated with keratanase and the digest was subjected to alkaline borohydride reduction, producing oligosaccharides with galactitol at their reducing ends. The reduced digest was chromatographed on a Nucleosil 5 SB anion-exchange column and individual oligosaccharides were isolated. One of these, oligosaccharide (I), was shown by 500 MHz 1H-n.m.r. spectroscopy to have the following structure: NeuAc alpha 2-3Gal beta 1-4GlcNAc(6SO4) beta 1-3Gal-ol (I) The structure of this oligosaccharide shows that keratan sulphate chains from bovine tracheal ring cartilage may be terminated with N-acetylneuraminic acid linked alpha (2-3) to an unsulphated galactose. Keratan sulphate chains were also isolated from bovine femoral head cartilage (15-18-month-old animals) using an identical protocol, but with keratanase which was subsequently shown to have sialidase activity. This yielded oligosaccharide (II), the unsialyated version of (I): Gal beta 1-4GlcNAc(6SO4) beta 1-3Gal-ol (II).