ATP-diphosphophydrolase activity in rat heart tissue

Espinosa, V; Galleguillos, M; Mancilla, M.; Garrido, J.; Kettlun A.M.; Tollados L.; Chayet L; Garcia, L.; Traverso-Cori A.; Antonieta Valenzuela M.

Keywords: substrate, hydrolysis, acid, muscle, inhibition, rat, enzyme, membrane, heart, fiber, animals, metal, ion, rats, cell, electrophoresis, acids, proton, specificity, synthase, metabolism, surface, apyrase, ph, receptor, metals, tissue, cations, female, adenosine, inhibitors, article, kinase, adenylate, myocardium, dephosphorylation, activity, concentration, skeletal, focusing, controlled, animal, study, nucleotide, amino, nonhuman, Animalia, isoelectric, triphosphate, triphosphatase, ecto, 5', nucleotidase, transporting, competitive, Hydrogen-Ion, Muscle,, Oligomycins, Rats,, Sprague-Dawley, Sarcolemma

Abstract

Extracellular nucleotides interact with specific receptors on the cell surface and are locally metabolized by ecto-nucleotidases. Biochemical characterization of the ATPase and ADPase activities detected in rat heart sarcolemma, under conditions where mitochondrial ATPase and adenylate kinase were blocked, supports our proposal that both activities correspond to a single enzyme, known as ATP-diphosphohydrolase or apyrase. The physiological function of this enzyme could be dephosphorylation of the nucleotides present in the interstitial heart compartment acting together with 5'-nucleotidase. Both hydrolytic activities have similarities in: sarcolemma localization, bivalent metal ion dependence, optimum pH, effect of several amino acid residue modifiers, competitive inhibition of nucleotide analogs, and broad nucleoside di- and triphosphate specificity. The ATPase activity could not be separated from the ADPase either through isoelectrofocusing or electrophoresis under acid conditions.

Más información

Título de la Revista: Biochemistry and Molecular Biology International
Volumen: 39
Número: 5
Editorial: Russian Acad Med Sci
Fecha de publicación: 1996
Página de inicio: 905
Página final: 915
URL: http://www.scopus.com/inward/record.url?eid=2-s2.0-0008138996&partnerID=q2rCbXpz