Oxidases NADPH

Dikalov and colleagues have detected 02 - during inflammation using a cyclic hydroxylamine.2 This was oxidised to a nitroxide in cultures of stimulated 

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Since it might be possible that the perturbation of membrane directly stimulated the NADPH-oxidase located on the cell membrane, which is the enzyme for the production of superoxide [24], the possibility was examined by the assay using detergent (Triton X-100) instead of polymers. At 0.001% of Triton X-100, no stimulation of superoxide release from DMSO-differentiated HL-60 cells was observed. At 0.01% of Triton X-100, a... 

Storch, J., and Ferber, E. (1988). Detergent-amplified chemiluminescence of lucigenin for determination of superoxide anion production by NADPH oxidase and xanthine oxidase. Anal. Biochem. 169 262-267. 

These stimuli elicit a complex series of responses that result in cell functions such as chemotaxis and release of inflammatory compounds, oxidants, and proteases. Probably related to chemotaxis is a rapid, transient actin polymerization response. Inflammation results in part from the release of proteases and myeloperoxidase normally stored in granules inside the cell (5) and from oxidants produced by an NADPH-oxidase system (6) located primarily... 

In this experiment FLPEP is the stimulus. When occupancy of new receptors is blocked by the addition of a formylpeptide receptor antagonist 30 s after stimulation (dashed line. Figure 8), the intracellular Ca remains elevated for 10 s, but then decays rapidly. The oxidant production rapidly plateaus. The first derivative of these data represent the time course of activation then turn-off of the NADPH oxidase system. The fact that Ca and oxidant production decay in concert may indicate that these events are linked in formylpeptide-stimulated cells. 

Superoxide is formed (reaction 1) in the red blood cell by the auto-oxidation of hemoglobin to methemo-globin (approximately 3% of hemoglobin in human red blood cells has been calculated to auto-oxidize per day) in other tissues, it is formed by the action of enzymes such as cytochrome P450 reductase and xanthine oxidase. When stimulated by contact with bacteria, neutrophils exhibit a respiratory burst (see below) and produce superoxide in a reaction catalyzed by NADPH oxidase (reaction 2). Superoxide spontaneously dismu-tates to form H2O2 and O2 however, the rate of this same reaction is speeded up tremendously by the action of the enzyme superoxide dismutase (reaction 3). Hydrogen peroxide is subject to a number of fates. The enzyme catalase, present in many types of cells, converts... 

Contain certain unique enzymes (eg, myeloperoxidase and NADPH-oxidase) and proteins... 

NADPH-oxidase j 2O2 + NADPH 20p + NADP -F H+ Key component of the respiratory burst Deficient in chronic granulomatous disease... 

The Respiratory Burst of Phagocytic Cells Involves NADPH Oxidase Helps Kill Bacteria... 

The electron transport chain system responsible for the respiratory burst (named NADPH oxidase) is composed of several components. One is cytochrome 6558, located in the plasma membrane it is a heterodimer, containing two polypeptides of 91 kDa and... 

NADPH oxidase is inactive in resting phagocytic cells and is activated upon contact with various ligands (complement fragment C5a, chemotactic peptides, etc)... 

Mutations in the Genes for Components of the NADPH Oxidase System Cause Chronic Granulomatous Disease... 

The H2O2 used as substrate is generated by the NADPH oxidase system. CT is the halide usually employed, since it is present in relatively high concentration in plasma and body fluids. HOCI, the active ingredient of household liquid bleach, is a powerful oxidant and is highly microbicidal. When applied to normal tissues, its potential for causing damage is diminished be-... 

Leukocytes are activated on exposure to bacteria and other stimuh NADPH oxidase plays a key role in the process of activation (the respiratory burst). Mutations in this enzyme and associated proteins cause chronic granulomatous disease. 

Ushio-Fukai M, Nakamura Y (2008) Reactive oxygen species and angiogenesis NADPH oxidase as target for cancer therapy. Cancer Lett 266 37-52 Valentin A, Rosati M, Patenaude DJ, Hatzakis A, Kostrikis LG, Lazanas M (2002) Persistent HIV-1 infection of natural killer cells in patients receiving highly active antiretroviral therapy. Proc Natl Acad Sci U S A 99(10) 7015-7020... 

Nitric oxide may also be an antioxidant by virtue of the feet that it can directly inhibit NADPH oxidase and thus prevent superoxide production (Clancy etaJ., 1992). This inhibition was reported to be independent of the reaction between nitric oxide and superoxide, which might be expected to be pro-oxidant (see Section 2.2.3). 

Clancy, R.M., Leszczynska-Piziak, J. and Abramason, S.B. (1992). Nitric oxide inhibits neutrophil superoxide anion production via a direct action on the NADPH oxidase. J. Clin. Invest. 90, 1116-1121. 

Watson, F., Robinson, J. and Edwards, S.W. (1991). Protein kinase c-dependent and independent activation of the NADPH-oxidase of human neutrophils. J. Biol. Chem. 266, 7432-7439. 

Thomas, P.D., Mao, G.D., Rabinovitch, A. and Posnansky, M.J. (1993). Inhibition of superoxide generating NADPH oxidase of human neutrophils by lazaroids. Biochem. Pharmacol. 45, 241-251. 

Figure 10.2 Possible sites for NADPH-oxidase assembly and activity in human neutrophils. Reprinted from Dahlgren and Karlsson, 1999. Copyright (1999), with permission from Elsevier Science.

That the oxidative burst is directly involved in the chemical defense of these algae is clear. This reaction can be inhibited by diphenyleneiodonium, a suicide inhibitor of NADPH-oxidase which suppresses both the production of reactive oxygen species and the natural resistance to epiphytic bacteria. In addition a role in the defense against endophytes was indicated, since pre-treatment with oligomeric guluronates resulted in decreased infection of L. digitata with the pathogen Laminariocolax tomentosoides [141]. 

NADPH oxidase deficiency and catalase positive organisms in chronic granulomatous disease... 

Knoller, S., Shpungin, S., and Pick, E. (1991) The membrane-associated component of the amphiphile-activated, cytosol-dependent superoxide-forming NADPH oxidase of macrophages is identical to cytochrome b559./. Biol. Chem. 266, 2795-2804. 

Mitochondria and NADPH Oxidase as Initiators of Oxygen Radical Overproduction in Heart Diseases... 

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