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.
Human proteins containing this domain
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- Holmgren A (1988). "Thioredoxin and glutaredoxin: small multi-functional redox proteins with active-site disulfide bonds". Biochem. Soc. Trans. 16 (2): 95–96. PMID 3286320.
- Holmgren A (1989). "Thioredoxin and glutaredoxin systems". J. Biol. Chem. 264 (24): 13963–13966. PMID 2668278.
- Holmgren A, Fernandes AP (2004). "Glutaredoxins: glutathione-dependent redox enzymes with functions far beyond a simple thioredoxin backup system". Antioxid. Redox. Signal. 6 (1): 63–74. PMID 14713336.
- Nilsson L, Foloppe N (2004). "The glutaredoxin -C-P-Y-C- motif: influence of peripheral residues". Structure. 12 (2): 289–300. PMID 14962389.
- Johnson GP, Goebel SJ, Perkus ME, Davis SW, Winslow JP, Paoletti E (1991). "Vaccinia virus encodes a protein with similarity to glutaredoxins". Virology. 181 (1): 378–381. PMID 1994586.
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