Kd | Fmut (Kdmut/Kd CCKBR-WT) | |
---|---|---|
nm | ||
CCKAR-WT | 0.18 ± 0.10 | 1.0 |
CCKAR-F198A | 0.53 ± 0.22 | 2.9 |
CCKAR-N102A | 0.45 ± 0.35 | 2.5 |
CCKAR-L103A | ND | NA |
CCKAR-F107A | ND | NA |
CCKAR-F109A | 0.14 ± 0.15 | 0.7 |
Inhibition of 125I-BH-CCK-8 binding by increasing concentrations of unlabelled CCK-8 was performed on CCKAR-WT and mutant receptors transiently expressed in COS-1 cells. The dissociation constants (K d) were determined using the nonlinear least-squares curve-fitting program, LIGAND (19) and are expressed as the mean ± standard error of three to nine experiments performed in duplicate. The factor Fmut represents the effect of the mutations on CCK-8 affinity and is calculated as theK d of the mutated receptor divided by theK d of the CCKAR-WT.
ND, not determined; NA, not applicable.