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The binding of [ 3 H]R‐PIA to A 1 adenosine receptors produces a conversion of the high‐ to the low‐affinity state
Author(s) -
Casadó V.,
Mallol J.,
Canela E.I.,
Lluis C.,
Franco R.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80978-c
Subject(s) - cooperativity , chemistry , cooperative binding , dissociation (chemistry) , receptor , ligand (biochemistry) , kinetics , hill differential equation , stereochemistry , biophysics , binding site , biochemistry , biology , physics , nonlinear system , exact differential equation , quantum mechanics , first order partial differential equation
Kinetic evidence for negative cooperativity on the binding of [ 3 H]R‐PIA to A 1 adenosine receptors was obtained from dissociation experiments at different ligand concentrations and from the equilibrium isotherm. The dissociation curves indicate that there is an apparent ligand‐induced transformation of high‐ to low‐affinity states of the receptor. At concentrations of 18.2 nM R‐PIA or higher there was only found the low‐affinity state of the receptor. In view of these results equilibrium binding data were analyzed by the usual two‐state model (assuming that there is an interconversion between them) and by the negative cooperativity model employing the Hill equation.