Tioredoksiini

Tioredoksiini is a small protein found in all living organisms, playing a crucial role in cellular redox homeostasis. It belongs to the thioredoxin family of proteins, characterized by a conserved active site containing a crucial cysteine-serine-cysteine motif. This motif allows tioredoksiini to act as a potent reducing agent, facilitating the reduction of disulfide bonds in other proteins. This reduction process is essential for the proper folding, function, and regulation of a vast number of cellular proteins.

The primary function of tioredoksiini is to maintain the reduced state of target proteins, counteracting oxidative stress. It achieves this through a reversible redox cycle. When oxidized, tioredoksiini's active site disulfide bond is reduced by thioredoxin reductase, an enzyme that utilizes NADPH as an electron donor. The reduced tioredoksiini can then efficiently reduce target proteins. This system is vital for numerous cellular processes, including DNA replication and repair, protein synthesis, and antioxidant defense. Dysregulation of tioredoksiini function has been implicated in various diseases, including cancer and autoimmune disorders.