The ability of BU 1 to transport halides (Cl -, Br -, I -) in nitrate or bicarbonate solutions was investigated using the lucigenin and SPBA assays, as all three halides are known to quench the fluorescence of these fluorescent probes. BU 1 was preincorporated in LUVs made of POPC and cholesterol (7:3 ratio) at 0.1 mol%. The transport experiments were initiated with the addition of 25 mM NaX. It should be noted that I -and Br -quench lucigenin and SPBA stronger than Cl -, resulting in lower fluorescence levels at the final plateaus of the transport experiments compared to the experiments with Cl -.