TABLE 2.
Ligand binding properties of substitutions in position ValIII:16, IleIII:16, PheV:13, ValV:17, LeuV:20, and PheVI:09 in the ghrelin receptor using [3H]MK-677 as a radioligand
The constructs were expressed in transiently transfected COS-7 cells. Values are shown ± S.E.
| Bmax | n | MK-677 Kd | n | Ghrelin Ki | n | |
|---|---|---|---|---|---|---|
| fmol/105 cells | nm | nm | ||||
| WT ghrelin R1a | 127 ± 16.7 | 4 | 1.91 ± 0.52 | 4 | 2.47 ± 0.42 | 7 |
| ValIII:16Ala (3.40) | 170 ± 14.9 | 4 | 3.03 ± 0.77 | 4 | 3.41 ± 0.82 | 6 |
| ValIII:16Ile | 165 ± 64.1 | 4 | 2.21 ± 0.4 | 4 | 2.89 ± 0.56 | 7 |
| ValIII:16Phe | 225 ± 6.46 | 4 | 6.3 ± 0.08 | 4 | 1.83 ± 0.01 | 5 |
| IleIII:19Ala (3.43) | 254 ± 55.6 | 3 | 4.79 ± 0.37 | 3 | 5.87 ± 0.14 | 3 |
| PheV:13Ala (5.47) | 208 ± 53.7 | 4 | 4.07 ± 0.96 | 4 | 1.78 ± 0.4 | 5 |
| ValV:17Ala (5.51) | 105 ± 15.7 | 4 | 2.1 ± 0.36 | 4 | 2.07 ± 0.59 | 5 |
| LeuV:20Ala (5.54) | 124 ± 34.1 | 4 | 4.08 ± 0.96 | 4 | 2.5 ± 0.36 | 6 |
| LeuV:20Ile | 164 ± 77.2 | 4 | 2.37 ± 1.22 | 4 | 2.43 ± 0.35 | 6 |
| LeuV:20Val | 238 ± 53.5 | 4 | 4.14 ± 1.08 | 4 | 2.35 ± 0.38 | 6 |
| LeuV:20Phe | 184 ± 25.6 | 4 | 5.31 ± 1.46 | 4 | 4.03 ± 1.21 | 6 |
| PheVI:09Ala (6.44) | 239 ± 52.3 | 4 | 4.43 ± 1.51 | 4 | 1.76 ± 0.39 | 7 |
| PheVI:09Leu | 338 ± 77.0 | 4 | 2.56 ± 0.6 | 4 | 3.66 ± 0.61 | 6 |
| PheVI:09Tyr | 280 ± 66.6 | 4 | 3.37 ± 0.64 | 4 | 2.41 ± 0.17 | 7 |