Evidence for the existence of O-linked sugar chains consisting of glucose and xylose in bovine thrombospondin

J Biochem. 1992 Apr;111(4):460-4. doi: 10.1093/oxfordjournals.jbchem.a123780.

Abstract

We have recently discovered unusual sugar chains [xylose-glucose and (xylose)2-glucose] linked to a serine residue in the first epidermal growth factor (EGF)-like domains of human and bovine coagulation factors VII, IX, and protein Z. The sequence surrounding this serine residue has a common -Cys-X-Ser-X-Pro-Cys- structure. Since one (residues 533-538) of the three EGF-like domains found in human thrombospondin contains the conserved sequence, we examined the presence of such O-linked sugar chains in bovine thrombospondin (bTSP) and its 210-kDa fragment. Component sugar analysis after pyridylamination (PA) of the acid hydrolysates of the S-aminoethylated proteins revealed that the proteins contain glucose (Glc) and xylose (Xyl). The oligosaccharide moieties released from intact bTSP by hydrazinolysis followed by pyridylamination were separated into two PA-oligosaccharides by high performance liquid chromatography (HPLC). Component sugar analysis of these PA-oligosaccharides indicated that they consist of Glc and Xyl in molar ratios of 1:1 and 1:2 (or 1:3). The reducing ends of both PA-sugar chains were found to be PA-Glc, as judged from the retention time of the HPLC peak of their hydrolysates. The presence of these PA-sugar chains in bTSP was confirmed by HPLC mapping with two different columns, using standard PA-di- or PA-trisaccharide derived from coagulation factors. From these results, we concluded that bTSP contains O-linked sugar chains consisting of Glc and Xyl in one of its three EGF-like domains.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aspartic Acid / analogs & derivatives
  • Aspartic Acid / chemistry
  • Carbohydrate Metabolism
  • Carbohydrate Sequence
  • Carbohydrates / chemistry*
  • Cattle
  • Chickens
  • Epidermal Growth Factor / chemistry
  • Glucose / chemistry*
  • Humans
  • Molecular Sequence Data
  • Molecular Weight
  • Oligosaccharides / chemistry
  • Oligosaccharides / metabolism
  • Oxidation-Reduction
  • Peptide Fragments / chemistry
  • Peptide Fragments / metabolism
  • Platelet Membrane Glycoproteins / chemistry*
  • Platelet Membrane Glycoproteins / metabolism
  • Thrombospondins
  • Xylose / chemistry*

Substances

  • Carbohydrates
  • Oligosaccharides
  • Peptide Fragments
  • Platelet Membrane Glycoproteins
  • Thrombospondins
  • 3-hydroxyaspartic acid
  • Aspartic Acid
  • Epidermal Growth Factor
  • Xylose
  • Glucose