Glutathione-ascorbate cycle

[2] However, monodehydroascorbate is a radical and if not rapidly reduced it disproportionates into ascorbate and dehydroascorbate (DHA).

Finally GSSG is reduced by glutathione reductase (GR) using NADPH as the electron donor.

Thus ascorbate and glutathione are not consumed; the net electron flow is from NADPH to H2O2.

[3][4] In plants, the glutathione-ascorbate cycle operates in the cytosol, mitochondria, plastids and peroxisomes.

[5][6] Since glutathione, ascorbate and NADPH are present in high concentrations in plant cells it is assumed that the glutathione-ascorbate cycle plays a key role for H2O2 detoxification.