RESEARCH ARTICLE Modulation of Na+/K+ ATPase Activity by Hydrogen Peroxide Generated through Heme

Leishmania amazonensisis a protozoan parasite that occurs in many areas of Brazil and causes skin lesions. Using this parasite, our group showed the activation of Na+/K+ ATPase through a signaling cascade that involves the presence of heme and protein kinase C (PKC) activity. Heme is an important biomolecule that has pro-oxidant activity and signaling capacity. Reactive oxygen species (ROS) can act as second messengers, which are re-quired in various signaling cascades. Our goal in this work is to investigate the role of hydro-gen peroxide (H2O2) generated in the presence of heme in the Na +/K+ ATPase activity of L. amazonensis. Our results show that increasing concentrations of heme stimulates the pro-duction of H2O2 in a dose-dependent manner until a concentration of 2.5 μM heme. To con-firm that the effect of heme on the Na+/K+ ATPase is through the generation of H2O2, we measured enzyme activity using increasing concentrations of H2O2 and, as expected, the activity increased in a dose-dependent manner until a concentration of 0.1 μMH2O2. To in-vestigate the role of PKC in this signaling pathway, we observed the production of H2O2 i