title: Differences in the distribution of O-sulphate groups of cell-surface and secreted heparan sulphate produced by human neuroblastoma cells in culture.
abstract: Confluent cultures of a human neuroblastoma cell line (CHP100) were incubated for 48 h with D-[1-3H]glucosamine and sodium [35S]sulphate. Radioactive glycosaminoglycans were analysed in the growth medium, rapid trypsin digest of the cell monolayer and a 1% (w/v) Triton/0.5 M NaOH extract of the final cell pellet. Sulphated glycosaminoglycans co-chromatographed when eluted by NaCl gradient from DEAE-cellulose. The medium contained mainly chondroitin sulphates, whereas the cell surface was enriched in heparan sulphate. Heparan sulphate was isolated as chondroitinase ABC-resistant material and treated with nitrous acid. Analysis of the scission products on Bio-Gel P-10 yielded fragments varying in size from single disaccharides to glycans consisting of nine disaccharide units. Cell-surface and medium heparan sulphate had respectively 52% and 54% N-sulphated glucosamine residues distributed in similar patterns along the polymer chain. The N:O-sulphate ratio of neuroblastoma heparan sulphate was 1.1:1. Analysis by high-voltage electrophoresis of di- and tetrasaccharide products produced by nitrous acid treatment showed that the distribution of 'O'-sulphate groups differed strikingly between heparan sulphates from the medium and cell-surface compartments. A di-O-sulphated tetrasaccharide was identified in both heparan sulphate species. The absence of detectable amounts of 35[S]sulphate associated with fragments larger than tetrasaccharide supports the close topographical association of N-sulphate and O-sulphate groups.
mesh_terms: D002478:Cells, Cultured; D002808:Chondroitin Lyases / Q000378:metabolism; D002850:Chromatography, Gel; D006025:Glycosaminoglycans / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D008970:Molecular Weight; D009447:Neuroblastoma / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D002808:Chondroitin Lyases; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D013431:Sulfates