Figure 6

Suggested role of GSTO (glutathione transferase omega) in cigarette smoke induced oxidative stress. Enzymes maintaining GSH homeostasis are important in protecting lung against cigarette smoke induced oxidative stress. GSTO belongs to the glutathione-S-transferase family (GST) that detoxifies toxic substrates present in tobacco smoke by a GSH-dependent mechanism. GSTO contains an N-terminal glutathione-binding domain and is able to bind and release GSH. GSH is one of the major antioxidants in airway secretions, and it can be hypothesized that GSTO participates in the maintenance of GSH homeostasis not only intracellularly but also in the extracellular space. ROS, reactive oxygen species; RNS, reactive nitrogen species; GSH, reduced glutathione; GSSG, oxidized glutathione; GR glutathione reductase; GCL, glutamate cysteine ligase; Grx, glutaredoxin; Prxe, peroxiredoxin, GPXe, glutathione peroxidase (extracellular); GSX, glutathione; ECSOD, extracellular superoxide dismutase; GSNO, nitrosoglutathione; GS, glutathione syntethase.