Correlation between microsomal (Na+ + K+)-ATPase activity and [3H]ouabain binding to heart tissue homogenates.
ATP plus Mg2+ plus Na+ supported [3H]ouabain binding to canine left ventricular tissue homogenates and microsomal (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity from the same tissue were measured. A linear relationship was found between the initial velocity of [3H]ouabain binding to tissue homogenates and microsomal (Na+ + K+)-ATPase activity from the same tissue in the presence and absence of in vivo bound digoxin. In vivo bound digoxin reduced both measurements. With tissue from digoxin-free hearts, a linear relationship was also obtained between the initial velocity and the maximum level of [3H]ouabain binding to tissue homogenate. Binding of [3H]ouabain to whole tissue homogenate is a convenient method for estimating (Na+ + K+)-ATPase activity in small left ventricular biopsy samples.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D004285:Dogs; D006352:Heart Ventricles / Q000201:enzymology / Q000378:metabolism; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism*; D011485:Protein Binding
D010042:Ouabain; D000251:Adenosine Triphosphatases