Chemoenzymatic synthesis of heparan sulfate and heparin

Heparan sulfate (HS) is a highly sulfated polysaccharide that plays essential physiological and pathophysiological functions. The biosynthesis of HS involves a series of specialised sulfotransferases, an epimerase and glycosyl transferases. The availability of these enzymes offers a promising method to prepare HS polysaccharides and structurally defined oligosaccharides. Given the fact that chemical synthesis of large HS oligosaccharides is extremely difficult, preparation of HS using a chemoenzymatic approach has gained momentum. This review article summarises recent progress on the development of a chemoenzymatic approach to prepare HS and HS oligosaccharides.