Derivatization and purification of bisecting tyrosinamide-oligosaccharides from ovotransferrin.
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.
Corradi da Silva
M L
ML
Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Ohio State University, Columbus 43210.
Tamura
T
T
Rice
K G
KG
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
D009844:Oligosaccharides; C036387:tyrosinamide; D003207:Conalbumin; D014443:Tyrosine; D000117:Acetylglucosamine