Comparison of receptor expression levels and CCK-8 affinities for wild-type and mutant CCK-BRs
| Receptor | Bmax | CCK-8 binding affinity, IC50 |
|---|---|---|
| fmol/104cells | nm | |
| Wild-type | 6.1 ± 0.8 (17) | 0.086 ± 0.01 (7) |
| T111A | 5.7 ± 1.1 (3) | 0.17 ± 0.03 (4) |
| S131A | 9.9 ± 2.4 (3) | 0.086 ± 0.01 (4) |
| S219A | 7.3 ± 0.5 (3) | 0.055 ± 0.01 (4) |
| W346A | 4.5 ± 0.7 (3) | 0.16 ± 0.03 (4) |
| V349A | 4.8 ± 0.8 (3) | 0.33 ± 0.101-a (5) |
| Y350A | 6.2 ± 0.5 (3) | 0.12 ± 0.03 (4) |
| N353A | 6.3 ± 0.7 (3) | 3.10 ± 0.601-a (6) |
| N353L | 3.9 ± 0.5 (3) | 0.15 ± 0.04 (3) |
| S379A | 7.4 ± 0.9 (3) | 0.085 ± 0.03 (4) |
Wild-type and mutant receptors were expressed at comparable densities and shared subnanomolar affinities for CCK-8, with the exception of the N353A mutant (see text). Data represent means ± standard errors from the number of independent experiments indicated in parentheses.
↵1-a p < 0.01, compared with corresponding wild-type values.