Scherman D, Henry J P
Biochim Biophys Acta. 1980 Jun 20;599(1):150-66. doi: 10.1016/0005-2736(80)90064-4.
The dye, oxonol-V (bis(3-phenyl-5-oxoisoxazol-4-yl)pentamethine oxonol), can be used to estimate the transmembrane potential of chromaffin granules. The potentials result either from a resting-state Donnan equilibrium (inside negative at pH 6.6) or from an ATP-driven proton pump. The fluorescence and absorption changes generated by ATP addition depended on the pH of the medium and the dye-to-vesicle ratio. Energization resulted in an increase in the number of oxonol-V binding sites, the new binding sites having the same dissociation constant. The rate of dye association was higher with resting than with energized chromaffin granules. The absorption change was associated with a red shift whereas the fluorescence change involved a quenching due to the increase in dye concentration on the membrane. The absorption and fluorescence changes varied linearly with the transmembrane potential difference when the interior potential was positive relative to the medium.
染料氧杂菁-V（双(3-苯基-5-氧代异恶唑-4-基)戊甲川氧杂菁）可用于估算嗜铬粒蛋白的跨膜电位。该电位要么源于静息态的唐南平衡（在pH 6.6时内部为负），要么源于ATP驱动的质子泵。添加ATP所产生的荧光和吸收变化取决于介质的pH值以及染料与囊泡的比例。激发导致氧杂菁-V结合位点数量增加，新的结合位点具有相同的解离常数。染料与静息嗜铬粒蛋白结合的速率高于与激发的嗜铬粒蛋白结合的速率。吸收变化与红移相关，而荧光变化则是由于膜上染料浓度增加导致的猝灭。当内部电位相对于介质为正时，吸收和荧光变化与跨膜电位差呈线性变化。
