Fig. 2.
Methods for the depolymerization of heparan sulfate. A representative HS hexasaccharide is shown with sulfate groups highlighted in green, glucuronic acid carboxyl groups in yellow, iduronic acid carboxyl groups in red, and acetate groups in blue. Heparin lyase digestion produces disaccharides with Δ4,5-unsaturated uronic acid for which information on the stereochemistry of C5 is lost. Deaminative cleavage produces disaccharides that contain anhydromannose (for CS GAGs, anhydrotalose is produced). Such disaccharides retain information on the stereochemistry of uronic acid C5 but lose information regarding the substitution of the hexosamine amino group.