Figure 6. pH dependence of Li⁺-coupled [³H]-serine uptake (1 μM) in TNBC cell lines. Uptake buffer contained LiCl and 5 mM tryptophan.

pH of the buffer was varied between 6.0 and 8.5. The pH 6.0 buffer was prepared using 25 mM Mes/Tris and the pH 8.5 buffer was prepared using 25 mM Tris/Hepes. The two buffers were mixed to prepare the buffers of other pH values. Serine uptake was measured in these buffers of different pH. Data are presented as means ± S.E (n=6). ′, MB231 cells; ≤, TXBR-100 cells.