Sequencing of heparan sulfate proteoglycans: identification of variable and constant oligosaccharide regions in eight heparan sulfate proteoglycans of different origins.

The sequence of the disaccharide units of eight heparan sulfate proteoglycans of different origins is described. All heparan sulfates contain 5 variable regions made of oligosaccharide blocks of disaccharides, namely, GlcUA(1-4)GlcNAc, GlcUA(1-4)GlcNS, IdoUA (1-4) GlcNS,6S,IdoUA-GlcNAc,6S, and IdoUA,2S(1-4)GlcNS,6S, besides two constant regions made of an internal tetrasaccharide (IdoUA-GlcNAc-IdoUA-GlcNS) and monosaccharides (GlcNS, and GlcNS,6S) at the non-reducing terminal. The N-acetylated region of the heparan sulfates is linked to the serine of the protein core through a trisaccharide of Xyl-Gal-Gal. Heparan sulfates differ from one another in terms of the number of disaccharides that compose each block.