Table 1.
Calculated TOR values associated with different extracellular conditions
| 0 mM Na pH 5.5 |
90 mM Na pH 7.5 |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| 5 αMG | 35 αMG | 5 αMG | |||||||
| Step (mV) | Slope (mV s−1) | I (μA) | TOR (s−1) | Step(mV) | Slope (mV s−1) | I (μA) | TOR (s−1) | I (μA) | TOR (s−1) |
| −0.31 ± 0.03 | −1.18 ± 0.12 | −0.32 ±0.04 | 2.71 ± 0.38 | −0.34 ± 0.05 | −3.53 ± 0.33 | −0.70 ± 0.06 | 8.00 ± 1.3 | −1.08±0.61 | 13.3±2.4 |
TOR5αMG and TOR35αMG at pH 5.5 are obtained directly from the slope/step ratios multiplied by the correction factor, f = 0.65, corresponding to the fraction of cotransporters moving in the electrical field of the membrane during a voltage pulse from +50 to −150 mV. This was done for each oocyte, and the mean values are shown (n = 14). The steps used for the calculation were obtained by subtracting the step measured in the presence of 0.2 mM Pz from the step in 5 or 35 mM αMG. The slopes were obtained by subtracting the slope in 0 mM αMG (pH 5.5) buffer from the slopes measured in the presence of 5 mM αMG or 35 mM αMG. Equation 1 was used to calculate TOR5αMG when 90 mM Na+ (pH 7.5) was in the bath.