Heparan sulfate substitutes

Residues of non-N-substituted 2-amino-2-deoxy-D-glucose constitute only a tiny fraction (if any) of the total amino sugar of heparin and heparan sulfate. Although free amino groups are produced in the biosynthesis20,23 of heparin (between stages 1 and 2, see Scheme 1), the small proportions occasionally found in heparin and heparan sulfate preparations are most probably the result of some N-desulfation during extraction, or purification, or both. 

Tuhkanen AL, Tammi M, Tammi R. CD44 substituted with heparan sulfate and endo-beta- galactosidase-sensitive oligosaccharides a major proteoglycan in adult human epidermis. J Invest Dermatol 1997 109 213-218. 

In view of the observations discussed above, it is thus possible that the initial stages of heparin and heparan sulfate biosynthesis are identical. Subsequent modifications of the product would then occur in the form of partial removal of the protein moiety and substitution of iV-sulfate groups for A -acetjd groups. The extent of these modifications may be a function... 

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