title: Analysis of lectin-specific cell surface glycoprotein on neuroblastoma cells.
abstract: The binding sites for the lectins wheat germ agglutinin, Ricinus communis agglutinin and concanavalin A on mouse neuroblastoma cell membranes were identified using SDS-gel electrophoresis in combination with fluorescent lectins. Ricinus communis agglutinin and wheat germ agglutinin were found to bind almost exclusively to a single polypeptide with an apparent molecular weight of 30 000. Concanavalin A labeled over 20 different polypeptides, most with molecular weights greater than 50 000. However, when the neuroblastoma cells were treated with concanavalin A so as to internalize all the concanavalin A binding sites visible at the level of the fluorescent microscope and the purified plasma membranes analyzed for their concanavalin A binding polypeptides, only four of the 20 glycopolypeptides were missing or significantly reduced in amount. Thus, these four high molecular weight concanavalin A-binding polypeptides appear to be the major cell surface receptors for concanavalin A. Binding studies with iodinated concanavalin A indicated that these polypeptides represented the high affinity concanavalin A binding sites (Kd = 2 . 10(-7) M). Low affinity concanavalin A binding sites were present on the cell surface after internalization of high affinity concanavalin A binding sites.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003208:Concanavalin A / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D037102:Lectins; D051379:Mice; D008970:Molecular Weight; D009447:Neuroblastoma / Q000378:metabolism*; D037121:Plant Lectins; D010940:Plant Proteins; D011952:Receptors, Concanavalin A / Q000378:metabolism*; D014909:Wheat Germ Agglutinins
chemical_list: D006023:Glycoproteins; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; D011952:Receptors, Concanavalin A; C017707:Ricinus communis agglutinin-1; D014909:Wheat Germ Agglutinins; D003208:Concanavalin A