The mixed disulfide of a Green-Fluorescent Protein with an Alexa 532 fluorescent label showed FRET, with quenching of the GFP emission. Reductive cleavage of this disulfide bond destroyed the FRET, giving a change in the ratios of fluorescence intensity at the wavelengths corresponding to the GFP and the Alexa dye. Cleavage by glutathione (second order rate constant at pH 7.4 was 1.18 ± 0.02 × 102 M−1 min−1) was faster than for sodium cyanoborohydride.
绿色荧光蛋白与 Alexa 532 荧光标记的混合二
硫键出现了 FRET,GFP 发射被淬灭。该二
硫键的还原性裂解破坏了 FRET,使 GFP 和 Alexa
染料相应波长的荧光强度比发生变化。
谷胱甘肽的裂解速度(pH 值为 7.4 时的二阶速率常数为 1.18 ± 0.02 × 102 M-1 min-1)快于
氰硼氢化钠。