Effects of the cytosol fraction and ATP on the kinetics of cAMP binding to human erythrocyte membranes.
The cytosol fraction of human erythrocytes as well as 1 mM ATP decreased the rate constant (Kl) of association of [3H]cAMP with human erythrocyte membranes. However, the effect of 1 mM ATP on the association kinetics was much greater than that of the cytosol fraction. Accordingly, the cytosol fraction and 1 mM ATP increased the rate constant (k-l) of dissociation of bound [3H]cAMP from the human erythrocyte membranes. However, the cytosol fraction affected the dissociation kinetics to a far greater extent than 1 mM ATP. Thus, although both cytosol and 1 mM ATP decreased the affinity of [3H]cAMP for binding sites on human erythrocyte membranes at equilibrium, the detailed mode of their action on the membrane [3H]cAMP binding sites appears to differ.
Tsukamoto
T
T
Laboratory of Biological Chemistry, Faculty of Agriculture, Saga University, Japan.
Yamakawa
Y
Y
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000242:Cyclic AMP / Q000493:pharmacokinetics*; D003600:Cytosol / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics
D000255:Adenosine Triphosphate; D000242:Cyclic AMP