Thioredoxin

• OMIM: 187700
• UniProt: P10599

Thioredoxins hot small proteins of about 100 amino acids and a disulfide bridge as an active center, which are of great importance as electron transferring cofactors in virtually all organisms. In the reduced form of thioredoxin act enzymatically as the oxidoreductase. In humans, two thioredoxins are known, depending on localization in the cytoplasm or mitochondria. Studies in the rat there is evidence of a role as an antioxidant and regulator of biomechanical signaling. Not to be confused with the thioredoxin family of proteins that contain a thioredoxin domain.

In plants, thioredoxins are significantly involved in the regulation of primary carbon metabolism: they control, among others, the activity of enzymes of the Calvin cycle, Rubisco Activase and support the assembly of CF1 - subunit of ATP synthase.

Structure

Trx proteins are approximately 12 kDa heavy. They carry in their active center, which is directed outwards, the sequence cysteine ​​-glycine -proline -cysteine, which is responsible for the electron transitions. The two cysteine ​​can take two different redox states: oxidized thioredoxin When the cysteine ​​residues are linked to a disulfide bond in the enzyme are reduced to two SH groups.