title: Properties and subcellular localization of adenosine diphosphatase in rat heart.
abstract: Some properties and subcellular localization of adenosine diphosphatase (ADPase) activity from rat heart have been investigated. The pH optimum was 7.4, maximal activity was found with 5 mM MgCl2, and the apparent Km was 20 microM. ADPase activity was strongly inhibited by NaF and AppNHp, and to a lesser extent by AMP and GppNHp. The enzyme was not inhibited by p-nitrophenylphosphate, beta-glycerophosphate, or pyridoxal phosphate. The distribution of ADPase activity in subcellular fractions obtained by differential centrifugation parallel ouabain-sensitive (Na+-K+)ATPase and 5'-nucleotidase activities, suggesting a plasma membrane-bound localization. The functional significance of ADPase in adenosine production and hemostasis is discussed.
mesh_terms: D000818:Animals; D001081:Apyrase / Q000302:isolation & purification / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D006352:Heart Ventricles / Q000201:enzymology; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity
chemical_list: D012969:Sodium Fluoride; D012964:Sodium; D010744:Phosphoric Monoester Hydrolases; D001081:Apyrase; D011188:Potassium; D002118:Calcium