Concanavalin A receptors associated with rat brain synaptic junctions are high mannose-type oligosaccharides.
Glycoproteins were isolated from a rat brain synaptic junction fraction by affinity chromatography on Concanavalin A-agarose. The isolated glycoproteins were digested with pronase and radiolabeled with 125I-Bolton Hunter reagent, and 125I-Concanavalin A-binding glycopeptides were isolated by chromatography on Concanavalin A-agarose. Treatment of the 125I-Concanavalin A-binding glycopeptides with either alpha-mannosidase or endo-beta-N-acetylglucosaminidase-C11 abolished their interaction with Concanavalin A. The pronase digest was reacted with endo-beta-N-acetylglucosaminidase-C11 and released oligosaccharides were reduced with NaB3H4. Following affinity chromatography on Concanavalin A-agarose, Concanavalin A-binding [3H]oligosaccharides were chromatographed on Biogel P4. Two major oligosaccharides corresponding to standard carbohydrates containing eight and five mannose residues were identified. Treatment of these oligosaccharides with alpha-mannosidase converted them to smaller saccharides having a mobility on Biogel P4 columns equal to the standard disaccharide mannose-beta-1-4-N'-acetylglucosamine. These results demonstrate that the Concanavalin A receptor activity associated with CNS synaptic junctions resides in asparagine-linked oligosaccharides of the high-mannose type.
D000818:Animals; D001921:Brain / Q000276:immunology*; D006020:Glycopeptides / Q000302:isolation & purification; D006023:Glycoproteins / Q000302:isolation & purification; D008358:Mannose / Q000032:analysis*; D008361:Mannosidases; D009844:Oligosaccharides / Q000302:isolation & purification*; D010944:Plants / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D011952:Receptors, Concanavalin A / Q000302:isolation & purification*; D013569:Synapses / Q000276:immunology*; D043323:alpha-Mannosidase
D006020:Glycopeptides; D006023:Glycoproteins; D009844:Oligosaccharides; D011952:Receptors, Concanavalin A; D008361:Mannosidases; D043323:alpha-Mannosidase; D008358:Mannose