title: Partial deglycosylation of blood-group-specific glycoproteins.
abstract: The time course for the partial deglycosylation of blood-group-specific glycoproteins from human ovarian-cyst fluids with 0.25 M-H2SO4/acetic acid and 6 M-HCl in methanol was studied. Either reagent readily removed about 80% of the carbohydrate from the glycoproteins to leave non-diffusible glycopeptides that contain N-acetylgalactosamine as the predominant sugar. Some changes in amino acid distribution were observed during the deglycosylation, which were attributed to an accelerated break-up of the nonglycosylated regions of the parent glycoprotein. The N-acetylgalactosaminyl-peptides isolated were judged to be polydisperse by gel filtration, and ion-exchange chromatography divided the glycopeptide population into several fractions with differing amino acid compositions. A Lumbricus terrestris hexosaminidase preparation was successful in removing almost all the remaining sugar from the glycopeptides, but caused further rupture of the peptide. When a per O-acetylated glycoprotein was treated with the H2SO4/acetic acid reagent the glycopeptide contained, in addition to N-acetylgalactosamine, about 50% of the sialic acid present in the parent glycoprotein, indicating that most of this sugar is located near the peptide end of the carbohydrate chains.
mesh_terms: D000085:Acetates; D000596:Amino Acids / Q000032:analysis; D001789:Blood Group Antigens; D002241:Carbohydrates / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D006020:Glycopeptides / Q000032:analysis; D006023:Glycoproteins; D006596:Hexosaminidases; D006801:Humans; D006851:Hydrochloric Acid; D000432:Methanol; D011402:Pronase; D013464:Sulfuric Acids
chemical_list: D000085:Acetates; D000596:Amino Acids; D001789:Blood Group Antigens; D002241:Carbohydrates; D006020:Glycopeptides; D006023:Glycoproteins; D013464:Sulfuric Acids; D006596:Hexosaminidases; D011402:Pronase; D006851:Hydrochloric Acid; D000432:Methanol