title: Quantitative mapping of the N-linked sialyloligosaccharides of recombinant erythropoietin: combination of direct high-performance anion-exchange chromatography and 2-aminopyridine derivatization.
abstract: A rapid quantitative analysis of the sialylated N-linked oligosaccharides of recombinant erythropoietin (EPO) expressed in Chinese hamster ovary (CHO) cells has been developed. The procedure utilizes a glycoamidase (glycopeptidase F) to release all of the N-linked oligosaccharides from the native glycoprotein, followed by direct chromatographic analysis using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection. The eight sialyloligosaccharides isolated from HPAEC were characterized by derivatizing with 2-aminopyridine followed by two-dimensional HPLC mapping of the pyridylaminated asialooligosaccharides (Tomiya et al., 1988, Anal. Biochem. 171, 73-90). Seven kinds of complex-type asialooligosaccharides were identified ranging from a biantennary structure to N-acetyllactosamine-extended tetraantennary structure. Approximately 3% of the terminal galactose residues of the oligosaccharides released from EPO were not sialylated whereas 97% contained an alpha(2-->3)-linked sialic acid. Quantitative oligosaccharide mapping of four different lots of EPO from CHO cells was performed to quantify the molar balance and distribution of the N-linked oligosaccharides. The sialyloligosaccharides were distributed with approximately 5% disialylated (single type), 20% trisialylated (six types), and 75% tetrasialylated (four types) oligosaccharides with an average molar recovery of 85% starting from 750 pmol of EPO.
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
authors.forename: K G
authors.initials: KG
authors.lastname: Rice
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
authors.forename: Y
authors.initials: Y
authors.lastname: Namiki
authors.forename: A D
authors.initials: AD
authors.lastname: Tran
authors.forename: P J
authors.initials: PJ
authors.lastname: Lisi
authors.forename: Y C
authors.initials: YC
authors.lastname: Lee
mesh_terms: D000581:Amidohydrolases; D000631:Aminopyridines; D000818:Animals; D016466:CHO Cells; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange / Q000379:methods; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D004921:Erythropoietin / Q000737:chemistry*; D006020:Glycopeptides / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011994:Recombinant Proteins / Q000737:chemistry*
chemical_list: D000631:Aminopyridines; D006020:Glycopeptides; D009844:Oligosaccharides; D011994:Recombinant Proteins; C016735:sialooligosaccharides; D004921:Erythropoietin; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; C032439:alpha-aminopyridine