Allosteric Modulators: The New Generation of Receptor Antagonist

Displacement of radioligand by allosteric antagonists. (A) An allosteric antagonist with α= 0.4 produces a low-magnitude shift to the right of the saturation binding curve; correspondingly, a shallow curve is observed for displacement of 60% maximally bound radioligand. In contrast (B), allosteric antagonists with lower values of α (here, α= 0.025) and orthosteric antagonists produce much larger shifts to the right of the saturation binding curve, resulting in a complete displacement of pre-bound radioligand.