Figure 12.

Sodium ion enhances sulfamethazine efflux via YdaH. (A) Accumulation of radioactive sulfamethazine in BL21(DE3)ΔabgTΔpabA/pET15bΩydaH cells with difference sodium ion concentrations. Cells showed a significant decrease in [³H]‐sulfamethazine accumulation in the presence of Na⁺. (B) Efflux of radioactive sulfamethazine in BL21(DE3)ΔabgTΔpabA/pET15bΩydaH cells in the presence of sodium or potassium ions. The presence of Na⁺ significantly enhances [³H]‐sulfamethazine efflux in BL21(DE3)ΔabgTΔpabA/pET15bΩydaH cells (black, control cells with the empty vector; red, 0 mM NaCl; magenta, 5 mM KCl; blue, 5 mM NaCl). The data showed in (A) and (B) are the cumulative average of three successive recordings. Error bars denote standard deviation (n = 3).