title: The chemical constitution of the proteoglycan of human intervertebral disc.
abstract: Proteoglycan was prepared from three pools of normal human intervertebral discs by extraction with buffered 4M-guanidinium chloride followed by CsCl-density-gradient ultracentrifugation. Chromatography on agarose (Bio-Gel A-150m) and on DEAE-cellulose suggested a single polydisperse proteoglycan species. The intrinsic viscosities of three preparations were 166, 122 and 168 ml/g. After degradation with 0.5M-KOH containing 0.02M-NaBH4, the glycosaminoglycans were recovered quantitatively and their Ca2+ salts separated into a hexuronate-rich fraction (fraction 1), which was precipitated in 0-45% (v/v) ethanol, and a hexose-rich fraction (fraction2), which was precipitated in 45-70% (v/v) ethanol. Qualitative and quantitative analyses of the glycosaminoglycans revealed fraction 1 to be chondroitin sulphate, and fraction 2 to be keratan sulphate; the latter was contaminated with protein and possibly a small amount of another glycosaminoglycan. For both glycosaminoglycans, plots of log(mol.wt.) against weight fell close to a normal distribution. The mode for chondroitin sulphate was close to 20000; that for keratan sulphate, 10000. A threefold range of molecular weight included the central 16-84% [+/- 1 S.D. of log(mol.wt.)] of the weight of both fractions.
mesh_terms: D000328:Adult; D002809:Chondroitin Sulfates / Q000032:analysis; D006025:Glycosaminoglycans / Q000302:isolation & purification; D006595:Hexosamines / Q000032:analysis; D006601:Hexoses / Q000032:analysis; D006603:Hexuronic Acids / Q000032:analysis; D006801:Humans; D007403:Intervertebral Disc / Q000032:analysis*; D007632:Keratan Sulfate / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009584:Nitrogen / Q000032:analysis; D011509:Proteoglycans / Q000032:analysis*; D014783:Viscosity
chemical_list: D006025:Glycosaminoglycans; D006595:Hexosamines; D006601:Hexoses; D006603:Hexuronic Acids; D011509:Proteoglycans; D002809:Chondroitin Sulfates; D007632:Keratan Sulfate; D009584:Nitrogen