Glutathione

One of the key metabolites involved in maintaining a reduced intracellular redox milieu is the tripeptide glutathione, which can be reversibly converted from the reduced form (GSH) to the oxidized form (glutathione disulfide; GSSG).



Glutathione is maintained in almost completely reduced form by glutathione reductases at the expense of NADPH.

The electrons of GSH are used e.g. to reduce peroxides through GSH peroxidases. They are also transferred non-enzymatically to the oxidized form of glutaredoxins, which in turn reduce target molecules like dehydroascorbate and proteins. Glutathione also plays a role in the detoxification program.

Under conditions of oxidative stress (high GSSG levels) one glutathione can be transferred to sulfhydryl groups of target proteins (glutathionylation) thus altering their activities. These glutathione moieties can be transferred to glutaredoxins.