Given the important role of oxidative stress and mitochondrial dysfunction in PD, in this study we sought to determine the significance of the mitochondrial Trx/Prx system in dopaminergic (DA) cells subjected to model toxicants implicated to cause parkinsonism e.g. paraquat (PQ) and 6-hydroxydopamine (6OHDA) [9]–[12]. The gene discussed is TXN; the disease is Parkinson disease.