This causes different overall changes in fluorescence intensities over the course of the experiments. After removal of the initial drop and normalization of the data, there appears to be more chloride transport at lower pH. However, the shapes of the curves are similar, as confirmed by the close values obtained for the half-lives (32 s at pH 6.3 and 41 s at pH 8.4, calculated as described in the Section 3.4). Similar effects have been observed when running the experiments with new vs. old bicarbonate solutions. We note that other mechanisms can also play a role in the apparent chloride/bicarbonate antiport observed in the lucigenin assay. Figure . Chloride/bicarbonate antiport by 2 pre-incorporated at 1:25000 transporter:lipid ratio. The liposomes were prepared in NaHCO3 solution with 0.8 mM lucigenin encapsulated. The transport was initiated with a 25 mM NaCl pulse. The curves are an average of 3 individual runs.