Synthetic heparin and heparan sulfate: probes in defining biological functions.

Heparin and heparan sulfate are glycosaminoglycans that modulate numerous biological processes. The desire to capture the structural diversity responsible for their functions provides notable issues during synthesis, including site-selective sulfonation, stereoselective glycosylation and the sheer number of probable targets at hand. With current advances in synthetic approaches, carbohydrate chemists generate these complex targets by chemical and enzymatic methods. Fondaparinux and a number of polysaccharides have been synthesized to probe anticoagulation and other biological functions. Moreover, a trove of structural information could be obtained by many analytical methods, which provide hints to the potential protein-binding sequences within the sugar chain. Further structure-activity relationship studies help unveil the secrets of the heparin/heparan sulfate code, providing potential candidates for drug development.