title: Adenine nucleoside 3'-tetraphosphates are novel and potent inhibitors of adenylyl cyclases.
abstract: 2'-Deoxyadenosine 3'-tetraphosphate (2'-deoxy-3'-A4P) and 2', 5'-dideoxyadenosine 3'-tetraphosphate (2',5'-dideoxy-3'-A4P) were synthesized, and their effects were tested on crude and purified forms of native adenylyl cyclases isolated from brain. Syntheses combined the method of alkoxide activation with the use of tribromoethyl phosphoromorpholino-chloridate as an initial phosphorylating agent. Inhibition of adenylyl cyclase was rapid in onset. With 2'-d-3'-A4P or 2',5'-dd-3'-A4P inhibition of a purified native enzyme conformed to a linear noncompetitive behavior with respect to substrate, metal-5'ATP. Order of potency was 2', 5'-dideoxy- > 2'-deoxyadenosine and 3'-tetraphosphate > 3'-triphosphate. Both mechanism of inhibition and rank order of potency were consistent with inhibition via the 3'-nucleotide-(P)-site on adenylyl cyclase. Neither 2',5'-dd-3'-ATP nor 2',5'-dd-3'-A4P had any effect on the activities of other adenosine nucleotide binding proteins such as Ca2+/calmodulin-sensitive cyclic nucleotide phosphodiesterase, Na+/K+-ATPase, or cAMP-dependent protein kinase. With purified adenylyl cyclase from bovine brain 2',5'-dd-3'-A4P and 2'-d-3'-A4P gave, respectively, IC50 values of 9.3 and 15 nM and Ki values of 23 and 53 nM. These 3'-nucleotides are the most potent regulators described for adenylyl cyclases.
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: R A
authors.initials: RA
authors.lastname: Johnson
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000378:metabolism; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000302:isolation & purification; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D003838:Deoxyadenine Nucleotides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D054306:Dideoxynucleotides; D007202:Indicators and Reagents; D007700:Kinetics; D010727:Phosphoric Diester Hydrolases; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: C114743:2',5'-dideoxyadenosine 3'-tetraphosphate; C114742:2'-deoxyadenosine 3'-tetraphosphate; D000067956:Adenylyl Cyclase Inhibitors; D003838:Deoxyadenine Nucleotides; D054306:Dideoxynucleotides; D007202:Indicators and Reagents; D017868:Cyclic AMP-Dependent Protein Kinases; D010727:Phosphoric Diester Hydrolases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D000262:Adenylyl Cyclases; D000254:Sodium-Potassium-Exchanging ATPase