The structures of asparagine-linked oligosaccharides of laccase excreted by sycamore (Acer pseudoplatanus L.) cells are reported. Peptic glycopeptides obtained from the laccase were treated with N-oligosaccharide glycopeptidase (EC 3.5.1.52) to release the oligosaccharide moieties. The oligosaccharides thus obtained were fractionated into six components by gel filtration, thin-layer chromatography, and high-performance liquid chromatography. The structures of the isolated oligosaccharides were determined by sugar analysis, exoglycosidase digestion, and methylation analysis in combination with high-resolution proton nuclear magnetic resonance spectroscopy. It was found that (1) the six oligosaccharides are a series of compounds of xylose-containing biantennary complex types that share as the core a common structural unit, i.e., Xyl-β(l-2)[Man-α(l-6)]Man-β(l-4)GlcNAc-β(l-4)[Fuc-α(1-3)]GlcNAc, and (2) mannose, N-acetylglucosamine, galactose, and fucose residues are additionally linked to the core as the outer chain moieties.
Publication DOI: 10.1021/bi00350a018Journal NLM ID: 0370623Publisher: American Chemical Society
Institutions: Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan, Department of Biochemistry, Nagoya City University Medical School, Nagoya, Japan, Centre National de la Recherche Scientifique, CENG, Grenoble, France, Research Institute for Biological Regulation School of Agriculture, Nagoya University, Nagoya, Japan, Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Tokyo, Japan
Methods: 1H NMR, TLC, acid hydrolysis, HPLC, enzymatic digestion, methylation analysis
Found