EC50 values (μm) and Hill coefficients for 5-HT activation of 141-Tyr mutant receptors (n = 3-6) (A) and [3H]granisetron binding affinities of Tyr mutants (B)
| A | ||
|---|---|---|
| 141- | EC50 ± SE | nH ± SE |
| Ala | 2.73 ± 0.15 | 2.68 ± 0.40 |
| Ser | 4.70 ± 0.38 | 2.02 ± 0.31 |
| Cha | 3.14 ± 0.40 | 1.92 ± 0.21 |
| Phe | 0.92 ± 0.06 | 2.80 ± 0.44 |
| 4-F-Phe | 1.32 ± 0.05 | 2.47 ± 0.17 |
| F5-Phe | 1.38 ± 0.08 | 1.89 ± 0.17 |
| Tyr (WT) | 1.16 ± 0.04 | 2.76 ± 0.20 |
| mTyr | 1.69 ± 0.06 | 3.24 ± 0.29 |
| 4-Me0-Phe | 3.36 ± 0.14 | 2.17 ± 0.16 |
| B | ||
|---|---|---|
| 141- | Kd (nm) | n |
| Ala | 8.97 ± 2.44* | 4 |
| Ser | NB | 8 |
| Phe | 0.98 ± 0.15 | 4 |
| Tyr (WT) | 0.32 ± 0.035 | 7 |
The asterisk indicates a significant difference (p<0.05) to Tyr. Substitutions have been approximately ordered by increasing size. NB, No binding; WT, wild type. The asterisk data in B are from Price and Lummis (2004).