The Cheng-Prusoff relationship: something lost in the translation.
For a variety of reasons, pharmacologists often construct 'inhibition curves' to evaluate antagonists rather than employing the more comprehensive 'Schild analysis'. There is a widespread perception that it is only possible to derive antagonist Kb values from such experiments via application of the Cheng-Prusoff equation, requiring knowledge of the agonist affinity at the receptor. In this article, Douglas Craig presents a practical examination of 'inhibition curve' methodology and demonstrates that it is a related equation requiring no knowledge of agonist affinity, rather than the Cheng-Prusoff equation, that affords theoretically valid estimates of antagonist Kb values from this technique.
Craig
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Department of Biochemical Sciences, Wellcome Research Laboratories, Beckenham, Kent, UK.
D004336:Drug Antagonism; D004347:Drug Interactions; D008433:Mathematics; D010600:Pharmacology