High-affinity radioligand binding to P-glycoprotein
Biochemical assay · Plasma membranes from P-gp-expressing Chinese hamster ovary CHrB30 cells; non-expressing AuxB1 membranes as specificity control. [1]
Saturation binding of radiolabeled XR9576 supported direct, high-affinity interaction with P-gp-containing membranes. No specific binding was observed in parental AuxB1 membranes (reported as data not shown).
| Endpoint | Reported result | Reference |
|---|---|---|
| Equilibrium dissociation constant of [3H]-XR9576 binding | Kd 5.1 ± 0.9 nM (n = 7) | [1] |
| Maximum specific binding capacity of [3H]-XR9576 | Bmax 275 ± 15 pmol mg−1 membrane protein | [1] |
Literature-Reported Treatment Conditions
- Treatment concentration
- 0–40 nM [3H]-XR9576
- Exposure duration
- 3 h at room temperature
- Method
- 2 µg CHrB30 membrane protein; nonspecific binding defined with 1 µM unlabeled GF120918
- Reported limits
- Salt form and lot not specified; saturation-assay vehicle not explicitly stated.
Methods and source locations
Compound reported in the paper: Tariquidar (XR9576); Compound label in the paper: [3H]-XR9576
Affinity applies to the radioligand/membrane assay, not a product lot or a functional IC50.
Methods: Materials and Specific drug binding to P-glycoprotein; Results: Potency and capacity; Figure 5a/caption
Equilibrium dissociation constant of [3H]-XR9576 binding: Rapid filtration saturation binding; fitted specific binding. Reported mean with uncertainty; Results do not explicitly define the ± statistic for this aggregate. — Results: Potency and capacity of drug binding to P-gp; Figure 5a and caption
Maximum specific binding capacity of [3H]-XR9576: Same saturation-binding design; Results link the estimate to XR9576 binding (n = 7). ± statistic not explicitly defined in that paragraph. — Results: Potency and capacity of drug binding to P-gp; Figure 5a and caption