Nitric oxide - reaction

Studies related to the mechanisms of nitric oxide reactions with transition metal complexes in this laboratory were supported by grants from the U.S. National Science Foundation, by a Collaborative UC/Los Alamos National Laboratory Research grant, by a grant from the U.S. Japan Cooperative Research Program (Photoconversion/ Photosynthesis) (NSF INT 9116346), and by a grant from the ACS Petroleum Research Fund. We thank the students and postdoctoral fellows at UC Santa Barbara who participated in this research and acknowledge collaborative studies with Dr. David Wink (National Cancer Institute, Bethesda MD, USA), Dr. Mikio Hoshino (RIKEN, Wako-shi, Japan) and Dr. Jon Schoonover (Los Alamos National Laboratory). 

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. 

In the chemiluminescent detection of nitrogen oxides, a constant source of ozone reacts with a metered air sample containing nitric oxide. Fontijn et al. suggested that this method could also be used for ozone detection by using a constant nitric oxide source for reaction with ozone in the air sample. The ozone-nitric oxide reaction is carried out at reduced pressure, to avoid quenching the chemiluminescent reaction. Detection of the emission in the spectral r on involved (600-3,000 nm) requires using a near-infrared-sensitive photomultiplier tube. The noise of such a photomultiplier tube is reduced by cooling it to about - 20 C. ... 

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... 

The catalytic oxidation of ammonia by air over platinum gauze at 900 °C gives nitric oxide (reaction 9.12), which is then oxidized to nitric acid by air and liquid water in a nitrous gas absorber (reactions 9.13 and 9.14) ... 

We conclude our discussion of nitric oxide reactions with nitrogen atoms with the report by Gatz, Smith, and Wise157 of the ionizing reaction... 

F15. Freeman, B. A., White, C. R., Gutierrez, H., Paler-Martinez, A., Tarpey, M. M., and Rubbo, H., Oxytgen radical-nitric oxide reactions in vascular diseases. Adv. Pharmacol. 34,45-69 (1995). 

In the absence of adequate kinetic data, these proposed reaction sequences are speculative in nature and will not be dignified by the term reaction mechanism. The sequences proposed Will be found valuable in both correlating many nitric oxide reaction and in suggesting additional experiments. 

If some other reactant was introduced into the system to remove nitric oxide in competition with the ozone-nitric oxide reaction, it was predicted that the ozone would accumulate. Nitrogen pentoxide was found to produce the predicted effect photolysis of the nitrogen dioxide-nitrogen pentoxide-oxygen system yielded substantial quantities of ozone. 

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... 

OH is converted to HO2 by reactions with carbon monoxide (Reaction (5.79)) and ozone (Reaction (5.90)), and HO2 is converted back to OH by reactions with nitric oxide (Reaction (5.92)) and ozone (Reaction (5.91)). The loss of HOx results from the conversion of OH and HO2 into soluble species like H2O2 and HNO3, followed by wet scavenging of these molecules through precipitation. 

Table VI Ammonia—Nitric Oxide Reaction Stoichiometry ...

Regardless of the exact reaction mechanism, these results suggest that the biological half-life of nitric oxide per se would be shortened by ONOO". On the other hand, if the net effect of the ONOO"/nitric oxide reaction was to increase the yield of nitrosothiol, it is conceivable that the biological effects of nitric oxide could be prolonged. 

Analysis of products from the reaction of phenol with nitric oxide, ONOO", or both (added simultaneously) provides some insight into possible reaction mechanisms as well as products that might be formed in vivo from phenolics such as tyrosine. Based on the apparent stoichiometry of the ONOO /nitric oxide reaction (see Fig. 2), a series of reactions were carried out in which ONOO was added at three different concentrations (0.2, 0.4, and 0.8 mM) in the absence and presence of a fixed concentration of nitric oxide (0.2 mM) added simultaneously. Ratios were chosen which would allow nitric oxide to remain in excess (0.2 mM ONOO" plus 0.2 mM nitric oxide), at stoichiometric concentrations (0.4 mM ONOO" plus 0.2 mM nitric oxide), and where ONOO" was in excess (0.8 mM ONOO" plus... 

The stoichiometry of the ONOO"/nitric oxide reaction appears to be approximately 2 1 based on the amount of ONOO required to completely abolish the nitric oxide signal. ONOOH undergoes spontaneous decay and can react as either a one- or two-electron oxidant. For this and other reasons the true stoichiometry cannot be assessed from these experiments. Regardless of the exact reaction ratio, the experiment shown in Fig. 1 illustrates that some nitric oxide will remain when an equimolar concentration of ONOO is added. 

Oxygen Radical-Nitric Oxide Reactions in Vascular Diseases... 

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