Enzymatic Synthesis of Homogeneous Chondroitin Sulfate Oligosaccharides

Chondroitin sulfate (CS) is a sulfated polysaccharide that plays essential physiological roles. Here, we report to utilize an enzyme-based method to synthesize a library of CS oligosaccharides consisting of 15 different CS oligosaccharides. The library covers 4-O-sulfated and 6-O-sulfated oligosaccharides with the size ranging from trisaccharide to nonasaccharide. We also demonstrate the synthesis of unnatural 6-O-sulfated CS pentasaccharides containing either a 6-O-sulfo 2-azido galactosamine or a 6-O-sulfo galactosamine residue. The availability of structurally defined CS oligosaccharides offers a novel approach to investigate the biological functions of CS.