Galactosaminoglycan Uronyl 2-Sulfotransferase
The glycosaminoglycan (GAG) side chains of proteoglycans exhibit structural diversity that allows participation in numerous biologic functions. Structural diversity is in part dependent on the abundance and placement of 2-sulfated uronyl residues. These components are highly abundant in the GAGs heparan sulfate and heparin but are infrequent in the galactosaminoglycans. For example, dermatan sulfate is predominantly composed of IdoA→GalNAc-4S and to a lesser extent GlcA→GalNAc-4. However, the 2-sulfated unit IdoA-2S→GalNAc-4S can also occur in minor amounts (5%–10% of total disaccharides) (Maimone and Tollefsen 1991). Similarly, chon- droitin sulfate principally contains GlcA→GalNAc-4S, GlcA→GalNAc-6S, or both; low amounts of GlcA-2S→GalNAc-6S may also be present (Cheng et al. 1994). Such paucity makes 2-sulfated uronyl residues ideal candidates for regulating selected biologic activities of dermatan sulfate/chondroitin sulfate. This chapter describes the recent isolation and characterization of the enzyme galactosaminoglycan uronyl 2- sulfotransferase, which is capable of adding this rare substituent to dermatan sulfate and chondroitin sulfate (Kobayashi et al. 1999).
KeywordsHeparan Sulfate Chondroitin Sulfate Dermatan Sulfate Chondroitin Sulfate Proteoglycan Donor Plasmid
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