Search results for "NADP"
showing 10 items of 242 documents
Oxidative stress in vascular disease: causes, defense mechanisms and potential therapies
2007
Endothelial cells control vascular homeostasis by generating paracrine factors that regulate vascular tone, inhibit platelet function, prevent adhesion of leukocytes, and limit proliferation of vascular smooth muscle. The dominant factor responsible for many of those effects is endothelium-derived nitric oxide (NO). Endothelial dysfunction characterized by enhanced inactivation or reduced synthesis of NO, alone or in combination, is seen in conjunction with risk factors for cardiovascular disease. Endothelial dysfunction can promote vasospasm, thrombosis, vascular inflammation, and proliferation of the intima. Vascular oxidative stress and increased production of reactive oxygen species con…
Pro-inflammatory effects of interleukin-17A on vascular smooth muscle cells involve NAD(P)H- oxidase derived reactive oxygen species.
2010
T cells are known for their contribution to the inflammatory element of atherosclerosis. Recently, it has been demonstrated that the Th17 derived cytokine IL-17 is involved in the pro-inflammatory response of vascular smooth muscle cells (VSMC). The aim of the present study was to examine whether reactive oxygen species (ROS) might be involved in this context. The effect of IL-17A on ROS generation was examined using the fluorescent dye 2′7′-dichlorodihydrofluorescein (H<sub>2</sub>DCF) in primary murine VSMC. IL-17A induced an increase in H<sub>2</sub>DCF fluorescence in VSMC, and this effect was blocked by the NAD(P)H-oxidase inhibitor apocynin and siRNA targeting …
A Deficiency in Respiratory Complex I in Heart Mitochondria from Vitamin A-Deficient Rats Is Counteracted by an Increase in Coenzyme Q
1997
Defects of NADH:coenzyme Q oxidoreductase (complex I) of mitochondria have been described in many congenital and acquired diseases. Administration of coenzyme Q (CoQ, ubiquinone) has been shown to benefit patients with some of these diseases. However, the mechanisms by which CoQ exerts the therapeutic effects are not clearly understood. A reason could be the lack of saturation of CoQ, in kinetic terms, for complex I activity. However, this hypothesis has not been proved in vivo because of the difficulty to incorporate CoQ into the mitochondrial membranes. We have found a deficiency in respiratory complex I in heart mitochondria from vitamin A-deficient rats which was accompanied by high CoQ…
NAD(P)H regeneration is the key for heterolactic fermentation of hexoses in Oenococcus oeni
2002
Oenococcus oeni (formerly Leuconostoc oenos) can perform malolactic fermentation, converting L-malate to L-lactate and carbon dioxide, in wines. The energy and redox potential required to support the growth of the micro-organism are supplied mainly by the consumption of carbohydrates via the heterolactic pathway. In the first steps of hexose metabolism two molecules of NAD(P)(+) are consumed, which must be regenerated in later reactions. The aim of this work was to test if aerobic growth of O. oeni promotes higher cell yields than anaerobic conditions, as has been shown for other lactic acid bacteria. O. oeni M42 was found to grow poorly under aerobic conditions with glucose as the only car…
Vascular oxidative stress, nitric oxide and atherosclerosis.
2014
In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxi…
Sildenafil protects epithelial cell through the inhibition of xanthine oxidase and the impairment of ROS production
2009
Recent reports suggest that xanthine oxidase (XO), a modified form of the native xanthine dehydrogenase enzyme, plays an important role in various forms of ischemic and vascular injuries, inflammatory diseases, and chronic heart failure. The XO inhibitors allopurinol and its oxidation product oxypurinol held considerable promises in the treatment of these conditions both in experimental animals and in human clinical trials. More recently, an endothelium-based protective effect of sildenafil, a well-known type-5 phosphodiesterase inhibitor, has been reported in preconditioning prior to ischemia/reperfusion in healthy human subjects. Based on the structural similarities between allopurinol an…
Engineering a Saccharomyces cerevisiae Wine Yeast That Exhibits Reduced Ethanol Production during Fermentation under Controlled Microoxygenation Cond…
2006
ABSTRACTWe recently showed that expressing an H2O-NADH oxidase inSaccharomyces cerevisiaedrastically reduces the intracellular NADH concentration and substantially alters the distribution of metabolic fluxes in the cell. Although the engineered strain produces a reduced amount of ethanol, a high level of acetaldehyde accumulates early in the process (1 g/liter), impairing growth and fermentation performance. To overcome these undesirable effects, we carried out a comprehensive analysis of the impact of oxygen on the metabolic network of the same NADH oxidase-expressing strain. While reducing the oxygen transfer rate led to a gradual recovery of the growth and fermentation performance, its i…
Structure and function of ferredoxin-NADP+-oxidoreductase
1987
The redox-enzyme ferredoxin-NADP-oxidoreductase has been shown to be activated by light and inactivated in the dark. This review will summarize recent data concerning the biochemical characterization of the enzyme compared to its in-vivo activation. Further-more the mechanism of this activation process is discussed as a conformational change caused by the light-driven proton gradient.
Kinetic and functional characterization of a membrane-bound NAD(P)H dehydrogenase located in the chloroplasts of Pleurochloris meiringensis (Xanthoph…
1996
Using isolated chloroplasts or purified thylakoids from photoautotrophically grown cells of the chromophytic alga Pleurochloris meiringensis (Xanthophyceae) we were able to demonstrate a membrane bound NAD(P)H dehydrogenase activity. NAD(P)H oxidation was detectable with menadione, coenzyme Q0, decylplastoquinone and decylubiquinone as acceptors in an in vitro assay. K m-values for both pyridine nucleotides were in the μmolar range (K m[NADH]=9.8 μM, K m[NADPH]=3.2 μM calculated according to Lineweaver-Burk). NADH oxidation was optimal at pH 9 while pH dependence of NADPH oxidation showed a main peak at 9.8 and a smaller optimum at pH 7.5-8. NADH oxidation could be completely inhibited with…
Determination of Plasma Lipid Hydroperoxides by an NADPH/NADP + Coupled Enzyme Reaction System. Evaluation of a Method
1998
Summary: Several techniques based on different principles have been proposed to measure lipid hydroperoxides. Enzymatic methods are sensitive and can be quite specific but they are subject to interference by inhibitors and not all are stoichiometric. The present work proposes some modifications of the Heath & Tappel (Anal Biochem 1976; 7:184—91) enzymatic method of determination of lipid hydroperoxides in order to standardize and automate it and to meet the analytical criteria required for a biological assay. The proposed new protocol and the automated assay give acceptable within-run and between-run precisions, with coefficients of variation of 3.34% and 5.80%, respectively, at the usual p…