APPENDIX2 - Diagram of Receptor Activation
A diagram showing how the acid-base, two-state model would produce receptor activation:
Where D is the binding ligand and RH and RL are the states of the receptor corresponding to the high and low affinity states respectively. G is the G protein and E is the enzyme within the cell that is activated by the alpha subunit of the G protein. DeltaRH represents the net shift produced by the relative unequal binding of D to RH and RL, which produces the receptor response (see http://www.bio-balance.com/Receptor2.htm and click on the picture to see the derivation of this model).