Parameters defining the quaternary complex model of allosteric interaction at GPCRs (Fig. 6)
| Parameter | Meaning |
|---|---|
| L | Receptor isomerization constant |
| K a | Equilibrium association constant for orthosteric ligand [A] |
| K b | Equilibrium association constant for allosteric modulator [B] |
| K g | Equilibrium association constant for G protein [G] |
| α | Activation cooperativity of [A] for the unliganded receptor |
| β | Activation cooperativity of [G] for the unliganded receptor |
| γ | Binding cooperativity between [A] and [G] |
| δ | Activation cooperativity between [A] and [G] |
| ε | Binding cooperativity between [B] and [G] |
| ζ | Activation cooperativity of [B] for the unliganded receptor |
| η | Activation cooperativity between [B] and [G] |
| θ | Binding cooperativity between [A] and [B] |
| ι | Activation cooperativity between [A] and [B] |
| κ | Binding cooperativity between [A], [B], and [G] |
| λ | Activation cooperativity between [A], [B], and [G] |