The distribution of sulfated uronic acid and hexosamine residues in heparin and heparan sulfate.

Heparins from various sources and heparan sulfate from umbilical cords have been subjected to Smith-degradation and reaction with nitrites. These procedures were effective for providing data relating to the distribution of sulfated iduronic acid residues in the molecule. Results indicated that heparins may have, as a prominent structural feature of the molecule, non-sulfated uronic acid distributed in single sequences, much as had been shown previously for N-acetylglucosamine residues. Sulfated uronic acid, however, may occur in multiple sequences of up to 5 or 6 residues. Heparan sulfate was found to have a major proportion of its ester sulfate on iduronic acid rather than hexosamine units, thereby having sections similar to those in heparins, though in considerably lower proportion.