Table 6.
Parameters of [3H]GDP binding to Gi/o, Gs/olf and Gq/11 subtypes of G-proteins
| Gi/o | Gs/olf | Gq/11 | ||||
|---|---|---|---|---|---|---|
| pKA | pα | pKA | pα | pKA | pα | |
| Carbachol | 6.90 ± 0.06 | −2.3 ± 0.2 | 6.87 ± 0.06 | −1.2 ± 0.1 | 6.87 ± 0.02 | −0.85 ± 0.09 |
| Furmethide | 7.13 ± 0.05 | −2.4 ± 0.2 | 7.10 ± 0.05 | −1.0 ± 0.1 | 7.17 ± 0.06 | −0.32 ± 0.05 |
| Oxotremorine | 7.93 ± 0.05 | −2.1 ± 0.2 | 7.97 ± 0.05 | −0.78 ± 0.08 | n.c. | n.c. |
| Pilocarpine | 7.23 ± 0.06 | −0.94 ± 0.08 | 7.19 ± 0.07 | −0.24 ± 0.04 | 7.25 ± 0.08 | −0.16 ± 0.03 |
Equilibrium dissociation constants (KA) of agonists and factors of cooperativity (α) between agonists and [3H]]GDP binding are expressed as negative logarithms. Constants were obtained by fitting Equation 7 to data from individual experiments shown in Figure 10. Data are means ± SEM of values from three independent experiments performed in quadruplicates.
GDP, guanosine diphosphate.