Glutaredoxin

Glutaredoxins  are small redox enzymes of approximately one hundred amino-acid residues which use glutathione as a cofactor. Glutaredoxins are oxidised by substrates, and reduced non-enzymatically by glutathione. In contrast to thioredoxins, which are reduced by thioredoxin reductase, no oxidoreductase exists that specifically reduces glutaredoxins. Instead, oxidized glutathione is regenerated by glutathione reductase. Together these components compose the glutathione system.

Glutaredoxins function as electron carriers in the glutathione-dependent synthesis of deoxyribonucleotides by the enzyme ribonucleotide reductase. Like thioredoxin, which functions in a similar way, glutaredoxin possesses an active centre disulfide bond. It exists in either a reduced or an oxidized form where the two cysteine residues are linked in an intramolecular disulfide bond.

Glutaredoxin has been sequenced in a variety of species. On the basis of extensive sequence similarity, it has been proposed that Vaccinia virus protein O2L is most probably a glutaredoxin. Finally, it must be noted that Bacteriophage T4 thioredoxin seems also to be evolutionary related. In position 5 of the pattern T4 thioredoxin has Val instead of Pro.

Subfamilies

 * Glutaredoxin subgroup

Human proteins containing this domain
GLRX;     GLRX2;     GLRX3;     GLRX5;     PTGES2;    TXNL3;