Analytical Glycobiology Keratan sulfate glycosaminoglycan from chicken egg white

Keratan sulfate (KS) was isolated from chicken egg white in amounts corresponding to ∼0.06 wt% (dry weight). This KShadaweight-averagemolecularweight of∼36–41 kDawith a polydispersityof∼1.3. The primary repeating unit present in chicken egg white KS was →4) β-N-acetyl-6-O-sulfo-D-glucosamine (1→ 3) β-D-galactose (1→with some 6-O-sulfo galactose residues present. This KSwas somewhat resistant to depolymerization using keratanase 1 but could be depolymerized efficiently through the use of reactive oxygen species generated using copper (II) and hydrogen peroxide. Of particular interest was the presence of substantial amounts of 2,8and 2,9-linkedN-acetylneuraminic acid residues in the form of oligosialic acid terminating the non-reducing ends of the KS chains. Most of the KS appears to be N-linked to a protein core as evidenced by its sensitivity to PNGase F.