Thioredoxins (Trx) are proteins that act as antioxidants catalyzing the reduction of other proteins. Thioredoxin, together with thioredoxin reductase (TrxR) and NADPH, comprises the thioredoxin system. The system is ubiquitous from Archea to man and supports several processes crucial for cell function, cell proliferation, antioxidant defense and redox-regulated signaling cascades. Multiple in vitro substrates for thioredoxin have been identified, including ribonuclease, choriogonadotropins, coagulation factors, glucocorticoid receptor, and insulin.
Amino-acid sequence analysis suggests that the presented protein contains a redox-inactive Trx-like domain.