Notes: L-Glutathione, oxidized (GSSG) is an oxidized form of the antioxidant L-glutathione (GSH; Item No. 10007461).{11632} It is produced upon reduction of hydroperoxide by glutathione peroxidases (GPXs) and can be reduced back to GSH through the NADPH-dependent enzyme glutathione reductase (GR).{61894,48903} The reduced glutathione-to-oxidized glutathione (GSH/GSSG) ratio has been used as an indicator of oxidative stress.{61894}