title: 5'-Nucleotidase activity of isolated mature rat cardiac myocytes.
abstract: Specific location of 5'-nucleotidase in the heart has been uncertain, some authors citing evidence for an exclusively non-myocyte location, while other data point to the existence of cytoplasmic and membrane-bound fractions. Single myocytes isolated from mature rat heart, and free of endothelial or interstitial cells, have been used to establish that muscle cells of the myocardium are rich in 5'-nucleotidase, exhibiting activity sufficient to account for the total myocardial content of this enzyme. All 5'-nucleotidase is accessible to extracellular AMP. Inhibitors of 5'-nucleotidase and adenosine transport have been used to establish that only the adenosine component of adenine nucleotides is taken up by myocytes, but hydrolysis of AMP by 5'-nucleotidase does not commit the adenosine formed to transport across the sarcolemmal membrane. Myocytes also have ecto-phosphatases which hydrolyse ADP and ATP.
authors.forename: J
authors.initials: J
authors.lastname: Bowditch
authors.forename: S
authors.initials: S
authors.lastname: Nigdikar
authors.forename: A K
authors.initials: AK
authors.lastname: Brown
authors.forename: J W
authors.initials: JW
authors.lastname: Dow
mesh_terms: D015720:5'-Nucleotidase; D000241:Adenosine / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D005260:Female; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D009708:Nucleotidases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013868:Thioinosine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000249:Adenosine Monophosphate; D013868:Thioinosine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009708:Nucleotidases; D015720:5'-Nucleotidase; C001789:4-nitrobenzylthioinosine; D000241:Adenosine