Thonzonium Bromide (Synonyms: NC 1264)

ATP-dependent proton transport assay

Purified vacuolar membrane vesicles (10 μg of protein) were incubated with alexidine dihydrochloride or thonzonium bromide at the indicated concentrations for 10 min on ice. ATP-dependent proton transport was measured as follows: Fluorescence quenching of ACMA was monitored (ex 410 nm, em 490 nm) upon the addition of 0.5mM ATP and 1mM MgSO4. Initial velocities were calculated for 15 s following addition of MgATP (n=2). The apparently enhanced rate measured with benzbromarone and tolazamide was not dose-dependent and was sustained in the controls, when the drugs were added to the reaction mixture prior to the membrane vesicles.

Cell lines

In wild-type yeast cells

Preparation method

Limited solubility. General tips for obtaining a higher concentration: Please warm the tube at 37 ℃ for 10 minutes and/or shake it in the ultrasonic bath for a while. Stock solution can be stored below -20℃ for several months.

Reaction Conditions

Yeast cells expressing pHluorin were grown overnight to mid-log phase (0.4–0.6 A600/ml) and pre-incubated with 100 μM drug in 0.2% DMSO.

Applications

Treatment of yeast cells with thonzonium bromide significantly lowers the pH to (pHcyt 6.22±0.02), 10 μM thonzonium bromide reduces cell growth, with the cells developing a mild vma phenotype at 37 °C. Moreover, thonzonium bromide completely prevents yeast growth at 50 and 100 μM concentrations.

References:

1. Chan CY, Prudom C, Raines SM, et al. Inhibitors of V-ATPase proton transport reveal uncoupling functions of tether linking cytosolic and membrane domains of V0 subunit a (Vph1p). J Biol Chem, 2012, 287(13): 10236-10250.