TABLE 3.
Effects of ionophores on glucuronide transport into subcellular vesiclesa
| Addition (concn) | Activity (%) |
|---|---|
| None | 100.0 |
| DNP (2 mM) | 10.9 |
| m-CCCP (5 μM) | 8.2 |
| Valinomycin (5 μM) | 27.2 |
| Nigericin (5 μM) | 48.8 |
| Valinomycin (5 μM) + nigericin (5 μM) | 9.3 |
a
Subcellular vesicles were prepared from E. coli NO2947(pWJL24) grown on minimal medium and induced with IPTG. After incubation for 2.5 min with or without additions as indicated, 20 mM ascorbate and 0.1 mM phenazine methosulfate were added, followed by 50 μM [14C]APG at 3.0 min. Initial rates of transport were measured in duplicate (15-s time point). The concentrations of ionophore used were shown to be maximal for effectiveness in separate dose-response measurements (not shown). All data were normalized to controls without ionophore performed with the same batch of vesicles.