Table 1.
Effects of various mutations on the activation of the sweet taste receptor by neohesperidin dihydrochalcone (NHDC) and aspartame (ASP)
| variant | NHDC EC50 (mM) | NHDC maximal signal (% of wt) | ASP EC50 (mM) | ASP maximal signal (% of wt) |
| wt | 0.1 ± 0.06 | 100 | 1.3 ± 0.1 | 100 |
| Q636A3.28 | 0.3 ± 0.2 | 61 ± 29 | 1.1 ± 0.1 | 70 ± 18 |
| Q637E3.29 | 1.5 ± 0.4 | 51 ± 13 | 1.7 ± 0.2 | 51 ± 10 |
| S640A3.32 | 0.8 ± 0.2 | 63 ± 18 | 1.4 ± 0.5 | 61 ± 40 |
| H641A3.33 | 1.2 ± 0.4 | 57 ± 22 | 1.8 ± 0.4 | 79 ± 70 |
| H721Aex2 | 0.8 ± 0.3 | 66 ± 10 | 1.6 ± 0.3 | 60 ± 40 |
| R723A5.36 | 0.2 ± 0.1 | 69 ± 71 | 1.5 ± 0.5 | 68 ± 50 |
| S729A5.42 | 0.2 ± 0.1 | 80 ± 16 | 0.9 ± 0.4 | 72 ± 20 |
| F730L5.43 | 0.9 ± 0.1 | 70 ± 18 | 1.7 ± 0.4 | 87 ± 27 |
| A733V5.46 | 0.1 ± 0.02 | 133 ± 8 | 1.1 ± 0.3 | 92 ± 80 |
| H734A5.47 | n.f. | -- | n.f. | -- |
| W775A6.48 | >3 | 30 ± 41 | 1.9 ± 0.2 | 20 ± 30 |
| F778A6.51 | 1.5 ± 0.4 | 50 ± 18 | 1.2 ± 0.1 | 80 ± 80 |
| V779A6.52 | 0.2 ± 0.1 | 88 ± 14 | 1.2 ± 0.3 | 52 ± 10 |
| L782A6.55 | >3 | 50 ± 11 | 1.7 ± 0.3 | 95 ± 90 |
| R790Qex3 | 0.1 ± 0.06 | 77 ± 15 | 0.9 ± 0.4 | 71 ± 30 |
| L798I7.36 | 0.2 ± 0.2 | 66 ± 26 | 0.9 ± 0.4 | 81 ± 5 |
Receptor variants that affect the NHDC response are shown in bold. Values are given as average over at least three independent experiments ± SD. n.f., no response to any tested sweetener. (>), EC50 not calculable because saturation is not reached (Additional file 2).