InterPro domain: IPR044627

This entry represents a group of dehydroascorbate reductases (DHARs), including DHAR1/2/3/4 from Arabidopsis. They act as thiol transferases but have no glutathione conjugating activity [ 1 ]. They catalyse the glutathione (GSH)-dependent reduction of oxidized ascorbate (dehydroascorbate, DHA). As a result, DHARs regenerate a pool of reduced ascorbate and detoxify reactive oxygen species (ROS) [ 2 ]. Unlike most other glutathione transferases, DHARs are monomeric [ 3 ]. DHAR2 and DHAR4 are predicted to be cytosolic, while DHAR3 is predicted to be chloroplastic, and DHAR1 is predicted to be mitochondrial. The cytosolic DHAR is important for ozone tolerance [ 3 ].

1. Functional divergence in the glutathione transferase superfamily in plants. Identification of two classes with putative functions in redox homeostasis in Arabidopsis thaliana. J. Biol. Chem. 277, 30859-69
2. Structural understanding of the recycling of oxidized ascorbate by dehydroascorbate reductase (OsDHAR) from Oryza sativa L. japonica. Sci Rep 6, 19498
3. Cytosolic dehydroascorbate reductase is important for ozone tolerance in Arabidopsis thaliana. Plant Cell Physiol. 47, 304-8