| Type: | Family | Name: | Glutaredoxin, GrxB |
| Description: | Glutaredoxins [, , ], also known as thioltransferases (disulphide reductases, are small proteins of approximately one hundred amino-acid residues which utilise glutathione and NADPH as cofactors. Oxidized glutathione is regenerated by glutathione reductase. Together these components compose the glutathione system []. Glutaredoxin functions as an electron carrier 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 disulphide bond []. It exists in either a reduced or an oxidized form where the two cysteine residues are linked in an intramolecular disulphide bond.Glutaredoxin has been sequenced in a variety of species. On the basis of extensive sequence similarity, it has been proposed [] that Vaccinia virusprotein O2L is most probably a glutaredoxin. Finally, it must be noted that Bacteriophage T4thioredoxin seems also to be evolutionary related. In position 5 of the pattern T4 thioredoxin has Val instead of Pro.This family includes the highly abundant Escherichia coliGrxB (Grx2) glutaredoxin which is notably longer than either GrxA or GrxC. Unlike the other two E. coli glutaredoxins, GrxB appears to be unable to reduce ribonucleotide reductase [], and may have more to do with resistance to redox stress []. | Short Name: | GRXB |
