Characterisation of oligosaccharides from the chondroitin/dermatan sulphates: 1H and 13C NMR studies of oligosaccharides generated by nitrous acid depolymerisation

The polymers chondroitin sulphate and dermatan sulphate have been fragmented by an anhydrous hydrazine/nitrous acid procedure. The resulting disaccharides from the polymer repeat sequences were reduced with NaBH4 and purified by ion exchange chromatography. Whereas enzymatic depolymerisation leads to the loss of the distinction between glucuronic and iduronic acids of CS and DS in the resultant disaccharides, nitrous acid depolymerisation retains these structures. Complete 1H and 13C NMR data have been derived for the major components which were shown to have the structures: GlcA-(β1→3)-anTal6S-ol (I) and l-IdoA-(α1→3)-anTal4S-ol (II), where anTal-ol represents (2,5)anhydro-d-talitol and 6S/4S represent O-ester sulphate groups at C-6/C-4 sites.

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► Chondroitin and dermatan sulphate have been depolymerised by hydrazinolysis/nitrous acid.
► The major disaccharides from dermatan sulphate and articular cartilage chondroitin sulphate have been isolated.
► The retention of the epimerisation status at C5 in the uronic acids of iduronic or glucuronic acids has been confirmed.
► Full 1H and 13C NMR data from the disaccharides are reported.