title: Derivatization and purification of bisecting tyrosinamide-oligosaccharides from ovotransferrin.
abstract: The major N-linked oligosaccharides from ovotransferrin were purified on a large scale. The oligosaccharides were released from 5 g of the glycoprotein using N-glycosidase F and isolated from a mixed bed ion exchange column. Reducing-oligosaccharides were reacted with ammonium bicarbonate to form a reducing-end glycosylamine which coupled with the N-hydroxysuccinimidyl ester of Boc-tyrosine, resulting in tyrosinamide-oligosaccharides. Resolution of tyrosinamide-oligosaccharides on reverse-phase (RP)-HPLC necessitated the removal of Boc by treatment with trifloroacetic acid. Two major tyrosinamide-oligosaccharides were isolated from preparative RP-HPLC and were characterized by 500 MHz proton NMR and FAB-MS. These were a biantennary and triantennary oligosaccharide, each possessing a bisecting GlcNAc residue extending from the central core Man residue. Thus, ovotransferrin represents an abundant glycoprotein source from which to prepare multi-micromole quantities of bisecting complex oligosaccharides which may find utility in exploring the ligand specificity of mammalian lectins or may be used as synthons to prepare novel glycoconjugates.
authors.affiliation: Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Ohio State University, Columbus 43210.
authors.forename: M L
authors.initials: ML
authors.lastname: Corradi da Silva
authors.forename: T
authors.initials: T
authors.lastname: Tamura
authors.forename: K G
authors.initials: KG
authors.lastname: Rice
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry; D000478:Alkylation; D000818:Animals; D002240:Carbohydrate Sequence; D002645:Chickens; D002845:Chromatography; D003207:Conalbumin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D010084:Oxidation-Reduction; D014443:Tyrosine / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D009844:Oligosaccharides; C036387:tyrosinamide; D003207:Conalbumin; D014443:Tyrosine; D000117:Acetylglucosamine