title: Inhibition of adenylyl cyclase by a family of newly synthesized adenine nucleoside 3'-polyphosphates.
abstract: The synthesis of a number of adenine nucleoside 3'-polyphosphates has been devised via a phosphotriester approach that combines the method of alkoxide activation with the use of 2,2,2-tribromoethyl phosphoromorpholinochloridate as a phosphorylating agent. The family of compounds included 3'ADP, 3'ATP, 2'-deoxy-3'ADP, 2'-deoxy-3'ATP, 2',5'-dideoxy-3'ADP, and 2',5'-dideoxy-3'ATP. Potency as inhibitors of adenylyl cyclases followed the order: 3'-mono- < 3'-di- < 3'-triphosphate and adenosine (Ado) < 2'-d-Ado < 2',5'-dd-Ado derivatives, with 2',5'-dideoxy-3'ATP exhibiting an IC50 of approximately 40 nM. This order was maintained with purified and recombinant forms of the type I enzyme. The nucleoside 3'-phosphates caused noncompetitive inhibition of the type I adenylyl cyclase from bovine brain, consistent with inhibition via the P-site. Inhibition was not due to hydrolytic products because this was minimal and inhibition kinetics by inorganic polyphosphates were inconsistent with those caused by the nucleoside 3'-polyphosphates. Only 3'ATP underwent cation-catalyzed, nonenzymatic hydrolysis, with the primary product being 2':3'-cAMP. Because 3'-ADP and 3'-ATP are naturally occurring, this class of compounds may physiologically regulate adenylyl cyclases and possibly other enzymes, mediating responses that include a reduction in 3':5'-cAMP levels and consequent reductions in protein kinase A-activated pathways.
authors.affiliation: Department of Physiology and Biophysics, State University of New York, Health Sciences Center, Stony Brook, New York 11794-8661, USA.
authors.forename: L
authors.initials: L
authors.lastname: Désaubry
authors.forename: I
authors.initials: I
authors.lastname: Shoshani
authors.forename: R A
authors.initials: RA
authors.lastname: Johnson
mesh_terms: D000227:Adenine Nucleotides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000302:isolation & purification; D000818:Animals; D001921:Brain / Q000201:enzymology; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D051381:Rats; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D000227:Adenine Nucleotides; D000067956:Adenylyl Cyclase Inhibitors; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000262:Adenylyl Cyclases