Table 3. IC50 (pM) of insulin, IGF1 and IGF2 to position 718 mutated full length receptors.
| Receptor |
Insulin IC50 (pM) Geometric mean (95% confidence intervals) |
IGF1 IC50 (pM) Geometric mean (95% confidence intervals) |
IGF2 IC50 (pM) Geometric mean (95% confidence intervals) |
|---|---|---|---|
| IR-A | 16.0 (7.2 to 35.6) | 705 (363 to 1371) | 95 (48 to 188) |
| IR-A P718A | 15.1 (9.8 to 23.4) | 1374 (1065 to 1773) | 218 (151 to 316) |
| IR-A P718E | 20.2 (8.9 to 45.9) | 1059 (799 to 1404)* | 154 (83 to 282)* |
| IR-A P718K | 16.3 (10.2 to 26.0) | 3672 (1591 to 8474)* | 595 (240 to 1475)* |
| IR-B | 13.0 (9.8 to 17.3) | 4360 (2540 to 7486) | 477 (259 to 877) |
| IR-B K718A | 15.2 (7.4 to 31.1) | 3622 (1603 to 8185) | 288 (160 to 517)* |
| IR-B K718E | 12.8 (10.1 to 16.7) | 1496 (831 to 2693)* | 225 (123 to 411)* |
| IR-B K718P | 11.9 (7.6 to 18.7) | 927 (429 to 2005)* | 155 (78 to 311)* |
The affinities of human insulin, IGF1 and IGF2 to IR-A, IR-B and position 718 mutated full length receptors were determined in SPA binding assay with displacement of 125I-insulin. The geometric mean of IC50 (pM) and the 95% confidence intervals are given for n = 3–5 independent experiments.
*) Significant difference (p < 0.05) determined by T-test between WT and mutant.