MINAMI, R., IKENO, T., IGARASHI, C., TSUGAWA, S. and NAKAO, T. Characterization of Keratan Sulfate Isolated from Liver Affected by Morquio Syndrome. Tohoku J. exp. Med., 1983, 139 (3), 321-326 Chemical structures of keratan sulfate (KS) isolated from the liver affected by Morquio syndrome type A (classical type) were investigated. In the KS from Morquio syndrome liver, the molar ratios of hexose, total sulfate, N-sulfate and sialic acid to hexosamine were 5.07, 0.90, 0.18 and 0.08, respectively, and about 10% of hexosamine consisted of galactosamine. The KS resulted in a production of oligosaccharides of relatively larger size after digestion with keratanase, as compared with bovine corneal KS. These findings strongly suggest that KS accumulated in the liver affected by Morquio syndrome may be derived from bony KS.