HUMAN AGGRECAN KERATAN SULFATE UNDERGOES STRUCTURAL-CHANGES DURING ADOLESCENT DEVELOPMENT

Alkaline borohydride-reduced keratan sulfate chains were isolated from human articular cartilage aggrecan from individuals of various ages ( 0-85 years old). The chains were structurally characterized using H-1 NMR spectroscopy, gel permeation chromatography, and oligosaccharide p rofiling (after digestion with the enzymes keratanase and keratanase I I). The results show that from birth to early adolescence (0-9 years) the levels of alpha(l-3)-fucosylation, alpha(2-3)-sialylation, and gal actose sulfation increase. Also, the weight-average molecular weight o f the chains increases. During maturation (9-18 years) the levels of f ucosylation and galactose sulfation continue to increase and alpha(2-6 )-sialylation of the chains occurs. In adult life (18-85 years) there is little change in the weight-average molecular weight of the chains, and the levels of fucosylation, sialylation, and sulfation remain fai rly constant.