title: Molecular and biosynthetic heterogeneity of fucosyl glycoproteins associated with rat brain synaptic functions.
abstract: The composition and biosynthesis of fucosyl glycoproteins present in rat brain synaptic membranes and synaptic junctions were investigated. Reaction with 125I-labelled fucose-binding protein (Lotus tetragonolobus) following sodium dodecyl sulphate gel electrophoresis identified 6--8 fucosyl glycoproteins in synaptic membranes but only three major high molecular classes (Mr = 180 000, 130 000 and 110 000) in synaptic junctions. Affinity chromatography on concanavalin A-Sepharose resolved each of the synaptic junctional fucosyl glycoproteins into concanavalin A-positive and negative components indicating the presence of at least six high molecular weight fucosyl glycoproteins in synaptic junctions. Following the administration of [3H]fucose synaptic membranes, synaptic junctions and post-synaptic densities incorporated isotope, the order of relative specific activities being synaptic membranes greater than synaptic junctions greater than post-synaptic densities. Fractionation of [3H]fucose-labelled synaptic junctions on concanavalin A-Sepharose revealed a time-dependent increase in the percentage of isotope associated with the concanavalin A-positive glycoproteins. The results demonstrate both molecular and biosynthetic heterogeneity of fucosyl glycoproteins associated with synaptic junctions.
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D003208:Concanavalin A; D005643:Fucose / Q000378:metabolism*; D006023:Glycoproteins / Q000096:biosynthesis* / Q000302:isolation & purification; D008970:Molecular Weight; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D013569:Synapses / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D003208:Concanavalin A; D005643:Fucose