title: Structure determination of the major N- and O-linked carbohydrate chains of the beta subunit from equine chorionic gonadotropin.
abstract: The carbohydrate moieties of equine chorionic gonadotropin alpha and beta subunits were released from the protein backbones by successive treatments with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F and alkaline borohydride and then fractionated by FPLC and HPLC. The major N- and O-linked glycans of the beta subunit were characterized by 500-MHz 1H-NMR spectroscopy, showing a remarkable structural heterogeneity for the N-glycosidically linked chains, comprising mono-, di-, tri- and tri'-antennary N-acetyllactosamine type of glycans, being partly alpha 1-6 fucosylated at the Asn-bound GlcNAc residue and having alpha 2-6 and alpha 2-3 linked N-acetyl- and N-acetyl-4-O-acetylneuraminic acid residues as sialic acid constituents. Significant differences in this respect were detected for the partially characterized glycans of the alpha subunit. The major part of the O-linked carbohydrate chains, occurring solely in the beta subunit, is formed by tri-, tetra-, penta- and hexa-saccharides. There are indications for the presence of oligo(N-acetyllactosamine) units in both the N- and O-linked glycans of the beta subunit.
authors.affiliation: Department of Bio-Organic Chemistry, Utrecht University, The Netherlands.
authors.forename: J B
authors.initials: JB
authors.lastname: Damm
authors.forename: K
authors.initials: K
authors.lastname: Hård
authors.forename: J P
authors.initials: JP
authors.lastname: Kamerling
authors.forename: G W
authors.initials: GW
authors.lastname: van Dedem
authors.forename: J F
authors.initials: JF
authors.lastname: Vliegenthart
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002850:Chromatography, Gel; D006064:Gonadotropins, Equine / Q000302:isolation & purification; D006736:Horses; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000302:isolation & purification
chemical_list: D002241:Carbohydrates; D006064:Gonadotropins, Equine; D009844:Oligosaccharides; D010446:Peptide Fragments