Editing Glutathione (section)

==Biochemical function==
Glutathione exists in reduced (GSH) and oxidized ([[Glutathione disulfide|GSSG]]) states.<ref name="Iskusnykh">{{cite journal |vauthors=Iskusnykh IY, Zakharova AA, Pathak D |title=Glutathione in Brain Disorders and Aging |journal=Molecules |volume=27 |issue=1 |date=January 2022 |page=324 |pmid=35011559 |pmc=8746815 |doi=10.3390/molecules27010324 |url= |doi-access=free }}</ref> The ratio of reduced glutathione to oxidized glutathione within cells is a measure of cellular [[oxidative stress]]<ref>{{cite journal | vauthors = Pastore A, Piemonte F, Locatelli M, Lo Russo A, Gaeta LM, Tozzi G, Federici G | title = Determination of blood total, reduced, and oxidized glutathione in pediatric subjects | journal = Clinical Chemistry | volume = 47 | issue = 8 | pages = 1467–9 | date = August 2001 | pmid = 11468240 | doi =  10.1093/clinchem/47.8.1467| url = http://www.clinchem.org/content/47/8/1467.long | doi-access = free }}</ref><ref name="pmid22995213">{{cite journal | author = Lu SC | title = Glutathione synthesis | journal =  Biochimica et Biophysica Acta (BBA) - General Subjects| volume = 1830 | issue = 5 | pages = 3143–53 | date = May 2013 | pmid = 22995213 | pmc = 3549305 | doi = 10.1016/j.bbagen.2012.09.008  }}</ref> where increased GSSG-to-GSH ratio is indicative of greater oxidative stress.

In the reduced state, the thiol group of cysteinyl residue is a source of one [[reducing equivalent]]. [[Glutathione disulfide]] (GSSG) is thereby generated. The oxidized state is converted to the reduced state by [[NADPH]].<ref name="Couto2013">{{cite journal | vauthors = Couto N, Malys N, Gaskell SJ, Barber J | title = Partition and turnover of glutathione reductase from Saccharomyces cerevisiae: a proteomic approach | journal = Journal of Proteome Research | volume = 12 | issue = 6 | pages = 2885–94 | date = June 2013 | pmid = 23631642 | doi = 10.1021/pr4001948 | url = https://pure.manchester.ac.uk/ws/files/27512240/POST-PEER-REVIEW-PUBLISHERS.PDF }}</ref> This conversion is catalyzed by [[glutathione reductase]]:
:NADPH +  GSSG + H<sub>2</sub>O →  2 GSH  +  NADP<sup>+</sup>  +  OH<sup>−</sup>