Compartmentalization of redox reactions is essential to all life forms. Protein activity can respond to changes in the local redox environment through the reversible oxidation of cysteine thiols. For the majority of cysteines in the proteome, this interaction takes place through equilibration with the glutathione pool; this raises the question whether this redox pool acts as a buffer, or instead as a sensitive media, transducing information from a local physiological state into protein function.
