Glutathione is reduced mainly by glutathione reductase (GR). But in my catfish species we are not been able to identify/detect any gene sequence for GR. Although we have been able to sequence other glutathione dependent enzymes (i.e. glutathione S-transferase, glutathione peroxidase). So I am wondering whether there are some other enzyme or an alternative pathway of glutathione reduction present in these catfish species! Please help.
Copper, iron and nickel ions can oxidize glutathione non-enzymatically (http://www.ncbi.nlm.nih.gov/pubmed/16337887).
Cheers, Christian
Yes, definitely there is. The reducing equivalents from NADPH enter the glutathione system either with the help of the FAD-dependent enzyme glutathione reductase (GR) or the thioredoxin reductase/thioredoxin couple (TrxR/Trx). The electrons are subsequently transferred to endogenous electrophilic compound such as glutathione disulfide (GSSG), yielding two molecules of reduced glutathione, GSH. The disulfide-reducing GR and TrxR could act as electron relays to tap into the NADPH pool, GSH is a versatile adapter molecule, and the glutathione system serves in most aerobic cells and organisms as the central metabolic network to remove or modify electrophilic compounds inherently present inside (endogenous) or outside (exogenous) the cell. Please read more on glutaredoxin systems (based in one reference that I had used the ff are on glutaredoxin systems - Methods Enzymol., 252 (1995), pp. 283–292; Biochim. Biophys. Acta, 1780 (2008), pp. 1304–1317; and Biochemistry, 48 (2009), pp. 1410–1423.)
- Badges
- Science method