O-Linked oligosaccharides of human articular cartilage proteoglycan.

O-linked oligosaccharides and keratan sulphate chains have been isolated from the proteoglycan subunits of human articular cartilage. The oligosaccharides possessed a size and chemical composition similar to the equivalent moieties present in the proteoglycan subunits of the Swarm rat chondrosarcoma. Furthermore, the size and chemical composition of the oligosaccharides showed little change with the age of the individual from whom the proteoglycan was obtained. In contrast, the keratan sulphate chains appeared to increase in chain length with increased age of the individual. The total number of keratan sulphate and oligosaccharide chains per core protein decreased with age, but it was not clear whether there was any change in the ratio of the two components with respect to one another.