The copolymeric structure of pig skin dermatan sulphate. Isolation and characterization of L-idurono-sulphate-containing oligosaccharides from copolymeric chains.
Dermatan sulphate was degraded by testicular hyaluronidase and an oversulphated fraction was isolated by ion-exchange chromatography. This preparation, which contained fairly long segments derived from the non-reducing terminal portion of the molecule, was subjected to periodate oxidation under acidic conditions. The oxidized iduronic acid residues were cleaved by reduction-hydrolysis (Smith-degradation) (Fransson & Carlstedt, 1974) or by alkaline elimination. The oligosaccharides so obtained contained both GlcUA (glucuronic acid) and IdUA-SO(4) (sulphated iduronic acid) residues. Copolymeric oligosaccharides obtained after alkaline elimination were cleaved by chondroitinase-AC into disaccharide and higher oligosaccharides. Since the corresponding oligosaccharides obtained by Smith-degradation were unaffected by this enzyme, it was concluded that the carbohydrate sequences were GalNAc-(IdUA-GalNAc)(n)-GlcUA-GalNAc. The iduronic acid-containing sequences were resistant to digestion with chondroitinase-ABC. It was demonstrated that the presence of unsulphated N-acetylgalactosamine residues in these sequences could be responsible for the observed effect. This information was obtained in an indirect way. Chemically desulphated dermatan sulphate was found to be a poor substrate for the chondroitinase-ABC enzyme. Moreover, digestion with chondroitinase-ABC of chondroitinase-AC-degraded dermatan sulphate released periodate-resistant iduronic acid-containing oligosaccharides. It is concluded that copolymeric sequences of the following structure are present in pig skin dermatan sulphate: [Formula: see text] N-acetylgalactosamine moieties surrounding IdUA-SO(4) residues are unsulphated to a large extent.
D000818:Animals; D002807:Chondroitin / Q000031:analogs & derivatives*; D002852:Chromatography, Ion Exchange; D003871:Dermatan Sulfate / Q000032:analysis*; D005965:Glucuronates; D006821:Hyaluronoglucosaminidase; D007067:Iduronic Acid / Q000302:isolation & purification*; D008190:Lyases; D009844:Oligosaccharides / Q000032:analysis; D010084:Oxidation-Reduction; D010504:Periodic Acid; D011108:Polymers; D013429:Sulfatases; D013431:Sulfates / Q000302:isolation & purification; D013552:Swine; D014574:Uronic Acids / Q000302:isolation & purification*
D005965:Glucuronates; D009844:Oligosaccharides; D011108:Polymers; D013431:Sulfates; D014574:Uronic Acids; D010504:Periodic Acid; D003871:Dermatan Sulfate; D007067:Iduronic Acid; D002807:Chondroitin; D013429:Sulfatases; D006821:Hyaluronoglucosaminidase; D008190:Lyases