MitoNEET, a [2Fe-2S] Protein, Catalyzes Glutathione Oxidation

Abstract MitoNEET is a [2Fe-2S]-containing enzyme proposed to function as a cellular redox-stress sensor. Here we found that purified mitoNEET binds to and directly acts on the cell’s central redox regulator, glutathione (GSH), to its corresponding disulfide (GSSG) without requiring oxygen. The conversion of GSH was monitored by HPLC using an optimized isocratic elution protocol and by spectroscopy with Ellman’s reagent. Additionally, mitoNEET’s novel enzyme activity is considered in the context of reactive electrophiles. Taken together, the discovery of mitoNEET’s GSH reactivity opens the path toward a deeper mechanistic understanding of how mitoNEET senses oxidative stress in the cell.