title: The effect of penultimate N-acetylgalactosamine 4-sulfate on chondroitin chain elongation.
abstract: Previous work has shown that odd-numbered oligosaccharides containing nonreducing terminal, non-sulfated N-acetylgalactosamine (GalNAc) or 6-sulfated GalNAc are excellent acceptors for enzymic addition of glucuronic acid (GlcA). However, the presence of a 4-sulfated GalNAc group blocks further addition. We have now used even-numbered oligosaccharides (a mixture of 4-sulfated, 6-sulfated, and non-sulfated) as acceptors of [3H]GalNAc to investigate the effect of sulfate residues on the GalNAc in the penultimate position. 3H-Labeled oligosaccharides were partially degraded with chondroitin AC lyase. The labeled trisaccharides, consisting of the added [3H]GalNAc and the nonreducing terminal disaccharides of the oligosaccharide acceptors, were then characterized. Both non-sulfated and mono-sulfated 3H-trisaccharides were observed. However, the 3H-trisaccharides were shown by chromatography with prepared standards to be non-sulfated or to be sulfated only at the 6-position. Thus the oligosaccharides containing a 4-sulfated, penultimate GalNAc at the nonreducing end did not serve as acceptors for [3H]GalNAc. Microsomes from mastocytoma cells, which make only chondroitin 4-sulfate, exhibited the same substrate specificity for exogenous oligosaccharide acceptors as did microsomes from chick cartilage which makes chondroitin 6-sulfate.
mesh_terms: D000116:Acetylgalactosamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002642:Chick Embryo; D002807:Chondroitin / Q000031:analogs & derivatives*; D002809:Chondroitin Sulfates / Q000096:biosynthesis*; D005688:Galactosamine / Q000031:analogs & derivatives*; D006132:Growth Plate / Q000378:metabolism; D012515:Mast-Cell Sarcoma / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism*; D009844:Oligosaccharides / Q000302:isolation & purification; D014316:Tritium; D014536:Uridine Diphosphate N-Acetylgalactosamine / Q000378:metabolism*; D014539:Uridine Diphosphate Sugars / Q000378:metabolism*
chemical_list: D009844:Oligosaccharides; D014539:Uridine Diphosphate Sugars; D014316:Tritium; C046735:N-acetylgalactosamine 4-sulfate; D014536:Uridine Diphosphate N-Acetylgalactosamine; D005688:Galactosamine; D002807:Chondroitin; D002809:Chondroitin Sulfates; D000116:Acetylgalactosamine