The Hill coefficients of SA1 and SA2 for Na+ at pH 7 and 8
| pH | Hill coefficient ± SEM | |
|---|---|---|
| SA1 | 7 | 1.04 ± 0.15 (n = 6) |
| 8 | 0.78 ± 0.27 (n = 4) | |
| SA2 | 7 | 1.15 ± 0.11 (n = 4) |
| 8 | 1.48 ± 0.17 (n = 4) |
The Na+ dependence of 3H-MeAIB uptake by SA1 and SA2 was measured in transfected HeLa cells. The linear phase of MeAIB uptake was measured, and the Na+ concentration varied by replacing the NaCl in Krebs'–Ringer's solution by choline chloride. The curves were fitted using Ultrafit (Biosoft) to determine the Hill coefficient.