Superoxide uncoupling product

Casteilla et al. [26] suggested that mitochondrial superoxide production is modulated by uncoupling proteins. It has also been proposed [27] that the production of superoxide by... 

Furthermore, as already mentioned above, the interaction of superoxide with NO synthase in vascular tissue may lead to uncoupling of this enzyme and increasing superoxide production [117]. Therefore, the overproduction of superoxide may affect superoxide/nitric oxide by different ways, resulting in cell injury. It is interesting that some biomolecules may be useful for improving this balance. Thus, 17(3-estradiol upregulated NO synthase expression and inhibited NADPH oxidase expression in human endothelial cells [136]. 

An effect secondary to the activation of enzymes by increased calcium levels can be increased production of reactive oxygen and nitrogen species. Thus, activation of mitochondrial dehydrogenases increases NADH production and electron transport, yet increased calcium uncouples ATP synthesis, and the excess electron generates superoxide. Calcium also activates nitric oxide synthetase. 

Loomis ED, Sullivan JC, Osmond DA, Pollock DM, Pollock JS. 2005. Endothelin mediates superoxide production and vasoconstriction through activation of NADPH oxidase and uncoupled nitric-oxide synthase in the rat aorta. J Pharmacol Exp Ther 315 1058-1064. 

Romero M, Jimenez R, Sanchez M, Lopez-Sepulveda R, Zarzuelo MJ, O Valle F, Zarzuelo A, Perez-Vizcaino F, Duarte J. 2008. Quercetin inhibits vascular superoxide production induced by endothelin-1 Role of NADPH oxidase, uncoupled eNOS and PKC. Atherosclerosis. 

Brand MD, Buckingham JA, Esteves TC, Green K, Lambert AJ, Miwa S, Murphy MP, Pakay JL, Talbot DA, Echtay KS (2004) Mitochondrial superoxide and aging uncoupling-protein activity and superoxide production. Biochem Soc Symp 71 203-213 Brennan RJ, Schiestl RH (1998) Chloroform and carbon tetrachloride induce intrachromosomal recombination and oxidative free radicals in Saccharomyces cerevisiae. Mutat Res 397 271-278... 

The P450 oxidation stoichiometry requires one molecule of oxygen and two electrons fi om NAD(P)H to add one oxygen atom to a substrate. If the ratio of reduced pyridine nucleotide (or oxygen) consumed to product formed is greater than one, the enzyme is said to be uncoupled. Uncoupling occurs when (a) the ferrous dioxy complex reverts to the ferric state by dissociation of superoxide. 

Endothelial nitric oxide synthase (eNOS). The enzyme responsible for nitric oxide production in human endothelium. Nitric oxide (NO) is a gas that relaxes vascular smooth muscle cells, induces vasodilatation and is critical for global vascular homeostasis. cNOS is a homodimer enzyme that couples oxygen consumption to L-arginine use to produce NO. In its uncoupled form, cNOS is rendered into a source of superoxides instead of NO. 

Stefanadis, C., and Channon, K.M., 2009b. Association of plasma asymmetrical dimethylarginine (ADMA) with elevated vascular superoxide production and endothelial nitric oxide synthase uncoupling implications for endothelial function in human atherosclerosis. European Heart Journal. 30 1142 1150. 

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