The role of sulphation of glycosaminoglycans in their structural and functional characteristics.

Abstract

The CD spectra in the far ultraviolet and the CD and ORD spectra of methylene blue-complexes (MB-complex) of glycosaminoglycans (GAG) with different sulphate contents were studied in comparison with their effect on the in vitro formation of collagen fibres. The following polyanions were investigated: Chondroitin sulphate-A with different sulphate contents, oversulphated chondroitin sulphate, heparin and dextran sulphate and their desulphated derivatives. It was observed that the MB-complex of polysaccharides with the same backbone structure, but with different sulphate contents might show ORD and CD spectra of exciton type, but of inverse sign. This phenomenon was interpreted on the basis of different types of aggregation of dye molecules bound to the polysaccharides. The biological effect of GAG changed also with the sulphate content. This suggests that it is the extent of sulphation rather than the glycosidic structure of GAG which determines their chiroptical and functional properties.