Changes in the redox equilibrium of cells influence a host of cell functions. Alterations in the
redox equilibrium are precipitated by changing either the glutathione/glutathione-disulfide
ratio (GSH/GSSG) and/or the reduced/oxidized thioredoxin ratio. Redox-sensitive green
fluorescent proteins (GFP) allow real time visualization of the oxidation state of the indicator.
Ratios of fluorescence from excitation at 400 and 490 nm indicate the extent of oxidation and
thus the redox potential while canceling out the amount of indicator and the absolute optical …