Protein denitration/modification by glutathione-S-transferase and glutathione peroxidase.

Peroxynitrite (PN)-pretreated histone III-S (NH) and reduced glutathione (GSH)-treated NH (NH(GSH)) were incubated with glutathione-S-transferase (GST) and glutathione peroxidase (GPX). Western blot analysis revealed decreased 3-nitrotyrosine immunoreactivity for NH(GSH), but not for NH. Additionally, increased nitrate was noted as an end product of these enzymatic reactions. The findings imply that GSH-treatment of NH may facilitate its conformational change in favor of subsequent enzymatic denitration and/or modification, which could be vital in relieving cellular oxidative stress and regulating NO/PN-mediated signal transduction cascade.