科研之友
微信
新浪微博
Facebook
分享链接
摘要
In our search for fluorescent uncouplers of oxidative phosphorylation, three esters of fluorescein, n-butyl-, n-octyl-, and n-dodecyl-oxycarbonyl-fluorescein C-4-FL, C-8-FL, C-12-FL) were synthesized and characterized. With increasing liposomal lipid content, the long-chain alkyl derivatives of fluorescein (C-8-FL, C-12-FL and commercially available C-18-FL), but not C-4-FL and unsubstituted fluorescein, exhibited an increase in fluorescence polarization reflecting the dye binding to liposomes. C-12-FL induced proton permeability in lipid membranes, while C-4-FL was inactive. In contrast to C-4-FL and C-18-FL, C-12-FL and C-8-FL increased the respiration rate and decreased the membrane potential of isolated rat liver mitochondria with half-maximal effective concentrations of 700 nM and 300 nM, respectively. The effect of C-n-FL on the respiration correlated with that on proton permeability of the inner mitochondrial membrane, as measured by induction of mitochondria swelling in the potassium acetate medium. Binding of C-8-FL to mitochondria depended on their energization, which was apparently associated with pH gradient generation across the inner mitochondrial membrane in the presence of a respiratory substrate. In wild-type yeast cells, C-12-FL localized predominantly in plasma membrane, whereas in AD1-8 mutants lacking MDR pumps, it stained cytoplasmic organelles with some preference for mitochondria. Fluorescent uncouplers can be useful as a tool for determining their localization in a cell or distribution between different tissues in a living animal by fluorescent microscopy.
- 出版日期2014-1
