Nitric oxide radical reactions with

Ruhho, H., Radi, R., Ansehni, D., Kirk, M., Bames, S., Butler, J., Fiserich, J. P., and Freeman, B. A., 2000, Nitric oxide reaction with hpid peroxyl radicals spares alpha-tocopherol during hpid peroxidation. Greater oxidant protection from the pair nitric oxide/alpha-tocopherol than alpha-tocopherol/ascorbate, J. Biol. Chem. 275 10812-10818. 

Rubbo H, Radi R, Anselmi D, Kirk M, Barnes S, Butler J, Eiserich JP, Freeman BA (2000) Nitric oxide reaction with lipid peroxyl radicals spares a-tocopherol during lipid peroxidation. Greater oxidant protection from the pair nitric oxide/a-tocopherol than a-to-copherol/ascorbate. J Biol Chem 275 10812-10818... 

Rubbo H, Radi R, Anselmi D (2000) Nitric oxide reaction with lipid peroxyl radicals spares a-tocopherol during lipid peroxidation. J Biol Chem 275 10812-10818... 

Mouse peritoneal macrophages that have been activated to produce nitric oxide by 7-interferon and lipopolysac-charide were shown to oxidize LDL less readily than unactivated macrophages. Inhibition of nitric oxide synthesis in the same model was shown to enhance LDL oxidation (Jessup etal., 1992 Yates a al., 1992). It has recently been demonstrated that nitric oxide is able to inhibit lipid peroxidation directly within LDL (Ho etal., 1993c). Nitric oxide probably reacts with the propagating peroxyl radicals thus terminating the chain of lipid peroxidation. The rate constant for the reaction between nitric oxide and peroxyl radicals has recently been determined to be 1-3 X10 M" s (Padmaja and Huie, 1993). This... 

Chemical/Physical. Products identified from the reaction of toluene with nitric oxide and OH radicals include benzaldehyde, benzyl alcohol, 3-nitrotoluene, p-methylbenzoquinone, and o, m, and p-cresol (Kenley et ah, 1978). Gaseous toluene reacted with nitrate radicals in purified air forming the following products benzaldehyde, benzyl alcohol, benzyl nitrate, and 2-, 3-, and 4-nitro-toluene (Chiodini et al., 1993). Under atmospheric conditions, the gas-phase reaction with OH radicals and nitrogen oxides resulted in the formation of benzaldehyde, benzyl nitrate, 3-nitrotoluene, and o-, m-, and p-cresol (Finlayson-Pitts and Pitts, 1986 Atkinson, 1990). 

The direct reaction of superoxide with nitric oxide is only one of at least four possible pathways that can form peroxynitrite (Fig. 40). For example, superoxide should also efficiently reduce nitrosyldioxyl radical to peroxynitrite. Alternatively, nitric oxide may be reduced to nitroxyl anion, which reacts with oxygen to form peroxynitrite. Superoxide dismutase could even catalyze the formation of peroxynitrite, since reduced (Cu or cuprous) superoxide dismutase can reduce nitric oxide to nitroxyl anion (Murphy and Sies, 1991). Thus, superoxide might first reduce superoxide dismutase to the cuprous form, with nitric oxide reacting with reduced superoxide dismutase to produce nitroxyl anion. A fourth pathway to form peroxynitrite is by the rapid reaction of nitrosonium ion (NO" ) with hydrogen peroxide. This is a convenient synthetic route for experimental studies (Reed et al., 1974), but not likely to be physiologically relevant due to the low concentrations of hydrogen peroxide and the difficulty of oxidizing nitric oxide to nitrosonium ion. 

As noted earlier, peroxynitrite is formed with a diffusion-controlled rate from superoxide and nitric oxide (Reaction 10). As both these radicals are ubiquitous species, which present practically in all cells and tissues, peroxynitrite can be the most important species responsible for free radical-mediated damage in biological systems. Moreover, it is now known that NO synthases are capable of producing superoxide and nitric oxide simultaneously (see Chapter 22), greatly increasing the possible rate of peroxynitrite production. In addition, another enzyme xanthine dehydrogenase is also able to produce peroxynitrite in the presence of nitrite... 

For example, the distonic anion radical of cyclopentadienylidene trimethylen-emethane reacts under mass spectrometer gaseous-phase conditions with carbon disulfide by sulfur abstraction and with nitric oxide by NO-radical addition. The first reaction characterizes the distonic anion radical mentioned as a nucleophile bearing a negative charged moiety. The second reaction describes the same anion radical as a species having a group with radical unsaturation (Zhao et al. 1996). 

Hurshman AR, Krebs C, Edmondson DE, Huynh BH, Marietta MA. Formation of a pterin radical in the reaction of the heme domain of inducible nitric oxide synthase with oxygen. Biochemistry 1999 38 15689-15696. 

Molecular imprinted polymer recognition and on line electrogenerated chemiluminescence detection. Most CL results from a direct oxidation reaction or an oxidation reaction with energy transfer. Commonly used oxidants include hydroperoxide, oxygen, potassium permanganate, ferricyanide, tetravalent cerium ion, lead dioxide and oxygen free radical such as superoxide anion ( 02 ), hydroxy radical ( OH) and nitric oxide (NO). 

Recently, a novel mechanism for hydroxyl radical production, which is not dependent on the presence of transition metal ions, has been proposed (7). This involves the production of peroxynitrite (ONOO ) arising from the reaction of nitric oxide (NO ) with superoxide (OJ), as shown in the following reactions ... 

Nitric oxide can act as a vitamin E-like inhibitor of radical chain propagation reactions via radical-radical reaction with cytotoxic species such as lipid peroxyi (LOO-) and aikoxyl (LO-) radicals. Nitric oxide reacts with yLO- and LOO- at near-diffusion-limited rates (for LOO-, ife = 1.3 X 10 M sec" ) (Padmaja and Huie, 1993). This rate constant... 

The rate of decomposition of organic compounds can often be increased by the addition of compounds such as Pb(CH3)4 or Hg(CH3)2, which introduce free radicals into the system. These compounds are said to sensitize the decomposition of the organic compound. In contrary fashion a compound such as nitric oxide combines with free radicals to remove them from the system. This inhibits the reaction by breaking the chains. 

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