title: Membrane topology as revealed by the binding of macromolecules.
abstract: Binding sites for specific molecules at the cell surface can be localized with the electron microscope in thin-section, freeze-etch and shadow-casting preparations. The receptors tested were binding sites to concanavalin A (Con A) labelled with haemocyanin and binding sites to insulin labelled with ferritin. Con A-binding sites were localized in endocrine cells of the pancreas and insulin-binding sites in isolated liver plasma membranes. The relevance of the topographical distribution of the binding sites to cell membrane organization is discussed.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D003208:Concanavalin A / Q000378:metabolism*; D005613:Freeze Etching; D005614:Freeze Fracturing; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism / Q000648:ultrastructure*; D008099:Liver / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D011485:Protein Binding; D011956:Receptors, Cell Surface
chemical_list: D007328:Insulin; D011956:Receptors, Cell Surface; D003208:Concanavalin A