Component of the glutathione system which performs several activities such as glutathione-dependent oxidoreductase, glutathione peroxidase and glutathione S-transferase (GST) activity (PubMed:11875065, PubMed:12684511). The disulfide bond functions as an electron carrier in the glutathione-dependent synthesis of deoxyribonucleotides by the enzyme ribonucleotide reductase. In addition, it is also involved in reducing cytosolic protein- and non-protein-disulfides in a coupled system with glutathione reductase. Required for resistance to reactive oxygen species (ROS) by directly reducing hydroperoxides and for the detoxification of ROS-mediated damage. GRX1 is less active as an oxidoreductase than GRX2 (PubMed:9571241, PubMed:18992757, PubMed:20417731). 2 glutathione + H2O2 = glutathione disulfide + 2 H2O 1-chloro-2,4-dinitrobenzene + glutathione = 2,4-dinitrophenyl-S-glutathione + chloride + H(+) glutathione + RX = a halide anion + an S-substituted glutathione + H(+) In response to heat shock and osmotic stress. Present with 3030 molecules/cell in log phase SD medium. Belongs to the glutaredoxin family.