Nitric oxide (NO) regulates several cellular functions via reversible regulation of mitochondrial respiration. Nitric oxide also reacts with mitochondrial superoxide anion to produce the potent oxidative species peroxynitrite that irreversibly hinders mitochondrial activities. Recent findings demonstrating that mitochondria produce NO via mitochondrial NO synthase (mtNOS) has intrigued several ...

Peroxynitrite, the reaction product of O2.- and .NO, is a toxic compound involved in several oxidative processes that modify proteins. The mechanisms of these oxidative reactions are not completely understood. In this study, using direct ESR at 37 degrees C, we observed that peroxynitrite induced in human blood plasma a long-lived singlet signal at g = 2.004 arising from proteins. This signal w...

BACKGROUND Diabetes-induced vascular dysfunction may arise from reduced nitric oxide (NO) availability, following interaction with superoxide to form peroxynitrite. Peroxynitrite can induce formation of 3-nitrotyrosine-modified proteins. RhoA/ROCK signaling is also involved in diabetes-induced vascular dysfunction. The study aimed to investigate possible links between Rho/ROCK signaling, hyperg...

Expression of several proteins of higher eukaryotes is post-transcriptionally regulated by interaction of iron-responsive elements (IREs) on their mRNAs and iron regulatory proteins (IRP1 and IRP2). IRP1 is a redox-sensitive iron-sulfur protein whose regulatory activity is modulated by iron depletion, synthesis of nitric oxide, or oxidative stress. IRP2 is closely related to IRP1, but it does n...

Peroxynitrite anion is a reactive nitrogen species formed in vivo by the rapid, controlled diffusion reaction between nitric oxide and superoxide radicals. By reacting with several biological molecules, peroxynitrite may cause important cellular and tissue deleterious effects, which have been associated with many diseases. In this work, an automated flow-based procedure for the in vitro generat...

The peroxynitrite anion is a potent oxidizing agent, formed by the diffusion-limited combination of nitric oxide and superoxide, and its production under physiological conditions is associated with the pathologies of a number of inflammatory and neurodegenerative diseases. Nitration of Escherichia coli iron superoxide dismutase (Fe-SOD) by peroxynitrite was investigated, and demonstrated by spe...

OBJECTIVE Peroxynitrite-mediated myocardial protein nitration has been associated with a depressed cardiac pump function. In the present study, an attempt was made to elucidate the molecular background of peroxynitrite-evoked alterations in the human myocardium. METHODS Isometric force generation was measured in permeabilized human ventricular myocytes and biochemical methods were employed to...

In this review we provide an analysis of the biochemistry of peroxynitrite and tyrosine nitration. Peroxynitrite is the product of the diffusion-controlled reaction between superoxide (O2•-) and nitric oxide (•NO). This process is in competition with the enzymatic dismutation of O2•- and the diffusion of •NO across cells and tissues and its reaction with molecular targets (e.g. guanylate cyclas...