title: Identification of purine binding sites on Torpedo acetylcholine receptor.
abstract: Electrophysiological studies from this and other laboratories have suggested a direct action of ATP on nicotinic acetylcholine receptors (nAChR). To determine the site of binding of this purine derivative, we have covalently modified the nAChR from Torpedo marmorata electrocytes employing 2-[3H]-8-azido-ATP as a photoactivable affinity label. Covalently attached radioactivity was predominantly found in the beta-polypeptide of the receptor. Based on the results of protection studies with several nAChR ligands whose target sites at the receptor are known, we conclude that the purine site(s) differ from those of acetylcholine and of physostigmine, galanthamine and related ligands, and those of local anesthetics.
authors.affiliation: Institute of Physiological Chemistry and Pathobiochemistry, Johannes-Gutenberg University Medical School, Mainz, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schrattenholz
authors.forename: U
authors.initials: U
authors.lastname: Roth
authors.forename: A
authors.initials: A
authors.lastname: Schuhen
authors.forename: H J
authors.initials: HJ
authors.lastname: Schäfer
authors.forename: J
authors.initials: J
authors.lastname: Godovac-Zimmermann
authors.forename: E X
authors.initials: EX
authors.lastname: Albuquerque
authors.forename: A
authors.initials: A
authors.lastname: Maelicke
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D000345:Affinity Labels / Q000378:metabolism*; D000818:Animals; D001386:Azides / Q000378:metabolism*; D001665:Binding Sites; D011978:Receptors, Nicotinic / Q000378:metabolism*; D014101:Torpedo
chemical_list: D000345:Affinity Labels; D001386:Azides; D011978:Receptors, Nicotinic; C017040:8-azidoadenosine 5'-triphosphate; D000255:Adenosine Triphosphate