Table 1.
Affinity and rate constants for estrogen receptor/ligand interactions
| Interaction | ka (M−1 s−1)a | kd (s−1)a | KD (nM) from biosensor (ligand-binding domain)a | KD (nM) from literatureb (wild type, full-length) | KD (nM) from literaturec (ligand-binding domain) |
|---|---|---|---|---|---|
| Agonist ligand | |||||
| prasterone | —d | —d | 4400 (2000) | 235–5400ef | 0.92,ik 0.3l |
| bisphenol A | 1.3 (1) × 106 | 2.7 (1) × 10−1 | 210 (10) | 195–32000g | |
| 17β-estradiol | 1.3 (6) × 106 | 1.2 (2) × 10−3 | 0.9 (4) | 0.05–15.0h | |
| estriol | 1.0 (2) × 106 | 1.3 (3) × 10−2 | 13 (5) | 1.4–9.3em | |
| estrone | 1.1 (2) × 106 | 9 (2) × 10−3 | 8 (3) | 0.3–626en | |
| diethylstilbestrol | 6.0 (7) × 106 | 5 (2) × 10−5 | 0.009 (3) | 0.04–11o | |
| Antagonist ligand | |||||
| tamoxifen | 4.5 (1) × 103 | 1.0 (1) × 10−3 | 220 (20) | 3.4–423p | 0.22l |
| 4-hydroxytamoxifen | 2.3 (1) × 103 | 4.1 (1) × 10−5 | 18 (1) | 0.1–96q | |
| nafoxidine | 6.3 (2) × 103 | 1.6 (1) × 10−4 | 25 (2) | 0.3–125er |
a Experimental error is reported in parentheses and was obtained from three or more independent analyses using different biosensors, sample preparations, and receptor densities on the flow cell surfaces.
b
Range of literature values reported (KD, KI, IC50, EC50, and RBA) for full-length wild-type human estrogen receptor-α.
c
Range of literature values reported (KD, KI, IC50, EC50, and RBA) for wild-type human estrogen receptor-α ligand-binding domain.
d
Not determined.
e
From both human and nonhuman estrogen receptor-α.
i
Determined using a three Cys→Ser mutant ER construct.
k
Ref. 10.
l
Ref. 33.