title: Potent inhibition of specific diadenosine polyphosphate hydrolases by suramin.
abstract: The cytosolic enzymes asymmetrical diadenosine tetraphosphate hydrolase (EC 3.6.1.17, Ap4Aase) and diadenosine triphosphate hydrolase (EC 3.6.1.29, Ap3Aase) are inhibited competitively by suramin. Ap4Aase and Ap3Aase were assayed in cytosolic rat brain extracts using fluorogenic analogues of the respective substrates diadenosine tetraphosphate (Ap4A) and diadenosine triphosphate (Ap3A). Ki values for suramin as inhibitor of Ap4Aase and Ap3Aase were 5 x 10(-6) M and 3 x 10(-7) M, respectively. Results indicate that suramin or suramin-like derivatives may be useful tools to investigate diadenosine polyphosphate cleaving enzymes and that the intracellular diadenosine polyphosphate metabolism may be a pharmacological target of suramin with biological and clinical implications.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, Tenerife, Canary Islands, Spain. protllan@ull.es
authors.forename: P
authors.initials: P
authors.lastname: Rotllán
authors.forename: C R
authors.initials: CR
authors.lastname: Rodríguez-Ferrer
authors.forename: A C
authors.initials: AC
authors.lastname: Asensio
authors.forename: S
authors.initials: S
authors.lastname: Oaknin
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000037:antagonists & inhibitors*; D000818:Animals; D001921:Brain / Q000378:metabolism; D015226:Dinucleoside Phosphates / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006868:Hydrolysis; D008297:Male; D009363:Neoplasm Proteins; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013498:Suramin / Q000494:pharmacology*; D014020:Tissue Extracts; D000099170:Bis(5'-adenosyl)triphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D015226:Dinucleoside Phosphates; D004791:Enzyme Inhibitors; D009363:Neoplasm Proteins; D010726:Phosphodiesterase Inhibitors; D010727:Phosphoric Diester Hydrolases; D013498:Suramin; D014020:Tissue Extracts; D000099170:Bis(5'-adenosyl)triphosphatase; C012275:P(1),P(5)-di(adenosine-5'-)pentaphosphate; C020733:diadenosine tetraphosphate; C011440:diadenosine triphosphate; C075829:diadenosine polyphosphate hydrolase; C020023:bis(5'-nucleosyl)tetraphosphatase (asymmetrical)