Mass spectrometric analysis of chondroitin sulfate-linked peptides

Chondroitin sulfate proteoglycans are integral components of the extracellular matrix. These are composed of repeating disaccharide units of glucuronic acid and N-acetylgalactosamine linked to a serine residue on the core protein through an oligosaccharide linker. The functions of chondroitin sulfate proteoglycans are regulated by the disaccharide heteropolymers attached to the core protein. The degree of sulfation and modifications on the oligosaccharide linker differs in different tissues depending upon its function. Here, we characterized the chondroitin sulfate-linked peptides using mass spectrometric-based glycoproteomics approach. We analyzed plasma, urine and fibroblasts from apparently healthy individuals by mass spectrometry. We identified 230 glycopeptides belonging to 25 chondroitin sulfate-linked proteoglycans.