Reactive oxygen species redox reactions leading

Redox reactions involving nitric oxide have important implications beyond their fundamental chemistry as demonstrated by the controversy in the biomedical literature regarding conditions under which generation of NO leads to the amelioration or the exacerbation of oxidative stress in mammalian systems (95). Oxidative stress is defined as a disturbance in the balance between production of reactive oxygen species (pro-oxidants) and antioxidant defenses (96). Reactive oxygen species include free radicals and peroxides as well as other reactants such as oxidative enzymes with metal ion sites in high oxidation states. The... 

The compleu ly different redox properties of reactive oxygen species in aprotic media or membranes lead to other routes of interaction of superoxide with hydrogen peroxide . Another mechanism independent to the Haber-Weiss reaction was found. In addition, there are stoichiometrically acting molecules like ascorbate or NADPH, which were thought to be involved in the generation of hydroxyl radicals via the equation... 

The reactions of Ru -pac complexes with biologically important oxidants and reductants are reviewed here to illustrate the most probable mechanism of the interaction between the [Ru (pac)H20] complexes and redox-active cellular species, viz. thio-proteins and H202- The reactivity of the [Ru (edta) (H20)] complex with various oxygen atom donors (ROOH= H2O2, BuOOH, HSOs") that leads to the formation of the active intermediate [Ru (edta)(0)] /[Ru (edta)OH] species can be followed kinetically as a function of [ROOH] and temperature at a fixed pH of 5.1 using stopped-flow and rapid scan techniques, as reported recently 53,54). 

These results Indicate that a variety of reactions may lead to Cu(I)/Cu(II) Interconversions In seawater. The results are summarised schematically In Figure 3 to demonstrate how copper redox cycling probably occurs. The basic features are a dynamic redox cycle Involving the relatively minor but klnetlcally reactive species which react with oxygen and hydrogen peroxide as described previously. They are probably reactive with ohter photochemlcally... 

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