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ATP‐diphosphophydrolase activity in rat heart tissue
Author(s) -
Espinosa Victoria,
Galleguillos Marco,
Mancilla Marta,
Garrido Jorge,
Kettlun Ana M.,
Collados Lucía,
Chayet Liliana,
García Lorena,
TraversoCori Aída,
Valenzuela M. Antonieta
Publication year - 1996
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549600201052
Subject(s) - apyrase , biochemistry , nucleotide , sarcolemma , adenylate kinase , enzyme , atpase , suramin , nucleoside triphosphate , adenine nucleotide , chemistry , atp hydrolysis , dephosphorylation , nucleoside , adenosine triphosphate , 5' nucleotidase , biology , phosphatase , receptor , membrane , gene
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.