title: Inhibition of extracellular and purified 5'-nucleotidase from rat heart.
abstract: 5'-Nucleotidase in perfused rat hearts, accessible to extracellular substrate [14C]-AMP contained in the perfusate, was compared to a partially purified 5'-nucleotidase from the same organ. Both activities were inhibited by ATP and, more effectively, by the ADP analog adenosine-alpha, beta-methylene diphosphate (APCP). The isolated enzyme showed a competitive inhibitor constant of 5.4 x 10(-8) M for APCP (Km of AMP = 1.4 x 10(-5) M). Although both activities were effectively inhibited by APCP, insufficient knowledge about the selectivity of this agent as a nucleotidase inhibitor does not permit a conclusion on whether or not the extracellular activity is identical to the partially purified enzyme.
mesh_terms: D000244:Adenosine Diphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D000818:Animals; D001667:Binding, Competitive; D005110:Extracellular Space / Q000201:enzymology*; D005260:Female; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D009708:Nucleotidases / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D010477:Perfusion; D051381:Rats
chemical_list: D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009708:Nucleotidases