Isolation and characterization of the O-glycan chain of the human vitamin-D binding protein.
On a highly purified preparation, the structure of the carbohydrate chain of the human vitamin D-binding protein was investigated and two genetic forms of this protein were considered (Gc 2 and Gc 1 proteins). It was found that only the Gc 1 protein (Gc1a isoform) was glycosylated, the glycan moiety representing about 1% of the protein. The structure of this O-glycosidically linked glycan was determined to be: Neu Ac alpha (2 leads to 3) Gal beta (1 leads to 3) GaINAc alpha (1 leads to 0) Ser (or Thr). A tetrasaccharidic O-glycan with two N-acetylneuraminic residues was also characterized. The vitamin D-binding protein is a rare example of a serum protein O-glycosylated only on some genetic forms.
D002352:Carrier Proteins / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D008401:Gas Chromatography-Mass Spectrometry; D006020:Glycopeptides / Q000032:analysis; D006801:Humans; D007525:Isoelectric Focusing; D011134:Polysaccharides / Q000302:isolation & purification; D014809:Vitamin D-Binding Protein
D002352:Carrier Proteins; D006020:Glycopeptides; D011134:Polysaccharides; D014809:Vitamin D-Binding Protein