Nitrogen monoxide and oxidative stress: composition and intensity of cellular oxidative bursts cocktail. A study through artificial electrochemical synapses on single human fibroblasts

Abstract

Peroxynitrite1 is a powerful oxidant produced in biological systems from superoxide (O 2˙-) and nitric oxide (˙NO). Peroxynitrite has been implicated in a host of disease states, including neurodegenerative disorders [1], chronic inflammation and autoimmune diseases [2,3], ischemia-reperfusion injury [4] and septic shock [5].The chemistry of peroxynitrite is complex and highly pHdependent [6,7]. Not only peroxynitrite anion (ONOO -) and its conjugated acid, peroxynitrous acid (ONOOH) (pK a = 6.8) are potent oxidants by themselves [8,9] but also they can lead to the production of secondary reactive species. Moreover, peroxynitrite is capable of nitrating aromatics [10] in a process that can be enhanced by metal centres and CO 2 [11].Despite of being a reactive and short-lived species, which precludes its direct isolation or measurement, peroxynitrite detection and quantitation can be achieved with the use of detector molecules as well as molecular footprints that take advantage of oxidation and nitration reactions. A good detector molecule should be sensitive and outcompete the multiple reactions that peroxynitrite can undergo in biological systems. Moreover, both detector molecules and footprints should be specific, in order to discriminate between the reactions of peroxynitrite from those of other species, including its precursors ˙NO and O2 -, and other ˙NO or O˙2 --derived oxidants. None of the detection systems used until now fulfil all these requisites, and a subtle knowledge of the biological chemistry of peroxynitrite is required in order to choose and utilise the best approach in different biochemical or biological systems. Peroxynitrite formationAlthough several possible routes lead to peroxynitrite formation, the main one in biology arises from the radicalradical combination reaction of ˙NO[12] and O˙2 - [13,14] NOThis is a diffusion-controlled reaction with a second order rate constant (k 2 ) that has been independently determined as 4. 1 The term peroxynitrite refers to the sum of peroxynitrite anion (ONOO-) and peroxynitrous acid (ONOOH). IUPAC recommended names for peroxynitrite anion, peroxynitrous acid, nitroso-peroxocarboxylate (ONOOCO 2 -) and nitric oxide are oxoperoxynitrate (1-), hydrogen oxoperoxynitrate, 1-carboxylato-2-nitrosodioxidane and nitrogen monoxide respectively.

Kinetic Magnetic‐Field Effect Involving the Small Biologically Relevant Inorganic Radicals NO and O2.−

“…[76] Two characteristic times derived from the parameter values given here are t d , the average time of diffusional separation of a radical pair, and t e , the dwell time of the radical pair in the reaction zone [Eqs. (21) and (22)]:…”

“…In vivo recombination of biogenic O 2 C À and NO to form oxoperoxonitrate (ONOO À ) [19] has been recognized as an important route to the oxidation of many biochemical targets. [20][21][22] Since a radical-pair recombination is involved, it would be interesting to find out whether such oxidation reactions with ONOO À are sensitive to a magnetic field.…”

“…In vivo recombination of biogenic O 2 C À and NO to form oxoperoxonitrate (ONOO À ) [19] has been recognized as an important route to the oxidation of many biochemical targets. [20][21][22] Since a radical-pair recombination is involved, it would be interesting to find out whether such oxidation reactions with ONOO À are sensitive to a magnetic field. The focus of interest would not be, in the first place, to account for external MFEs on biological systems, but rather to apply such MFEs as diagnostic tools for identifying the mechanism leading to some biochemical oxidation products.…”

The N–B Interaction through a Water Bridge: Understanding the Chemoselectivity of a Fluorescent Protein Based Probe for Peroxynitrite

“…9-10 In particular, peroxynitrite, a highly reactive oxidative and nitrosative species with a very short half-life (< 10 ms) in biological systems, plays important roles in cell signaling, stress response, and pathogenesis. 11 Peroxynitrite can mediate protein nitration to modulate enzymatic activity and protein stability, 12-14 increase immunogenicity of modified proteins, 15 induce protein-protein interaction by mimicking phosphotyrosine, 16 and cross-talk with tyrosine kinases and phosphatases by altering their substrate structures. 13,17 As a strong oxidant and an excellent nucleophile, peroxynitrite and its secondary metabolites, such as hydroxyl radical (•OH), carbonate radical (CO 3 •− ), and nitric dioxide radical (•NO 2 ) can also induce DNA damage, lipid peroxidation, and protein oxidation and nitration, thereby leading to deregulated signal transduction, impaired physiological function, and cell death.…”

Electropolymerized Manganese Tetraaminophthalocyanine Thin Films onto Platinum Ultramicroelectrode for the Electrochemical Detection of Peroxynitrite in Solution

“…Indeed, it reacts with multiple targets such as thiols, transition metal centers and CO 2 [1, 8 -10]. In the absence of direct targets, PON decomposes within less than 2 seconds at physiological pH, at 37 8C, giving mainly nitrate [1,10,11].…”