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Harvey Lectures
Review
Topics: Animals; Bacteria; Enzyme Induction; Humans; Hydroxides; Hydroxyl Radical; Inflammation; Isoenzymes; Perfusion; Superoxide Dismutase; Superoxides
PubMed: 6100676
DOI: No ID Found -
Journal of Biological Inorganic... Jun 2002A superfamily of mononuclear iron proteins, originally named desulfoferrodoxin and neelaredoxin, has been identified by in vivo and in vitro studies as scavengers of the... (Review)
Review
A superfamily of mononuclear iron proteins, originally named desulfoferrodoxin and neelaredoxin, has been identified by in vivo and in vitro studies as scavengers of the superoxide anion radical. These proteins, whose genes are present in all the so-far known genomes from anaerobes and in the microaerophilic pathogen Treponema pallidum, show not only a considerable amino acid sequence identity but, most importantly, a common active iron site, Fe[His(4)CysGlu], in the oxidized state which loses the glutamate ligand in the reduced form. The experimental evidence for the activity of these proteins as superoxide dismutases or as donor:superoxide oxidoreductases is discussed in this Commentary, giving particular emphasis to the neelaredoxin from the hyperthermophilic archaeon Archaeoglobus fulgidus.
Topics: Bacterial Proteins; Carrier Proteins; Desulfovibrio; Iron-Binding Proteins; Models, Molecular; Oxidoreductases; Protein Conformation; Pyrococcus furiosus; Superoxide Dismutase; Superoxides; Treponema pallidum
PubMed: 12072976
DOI: 10.1007/s00775-002-0363-1 -
Frontiers in Bioscience : a Journal and... May 1997Chronic inflammation is known to be associated with enhanced production of both nitric oxide (NO) and reactive oxygen species such as superoxide (O2-) and hydrogen... (Review)
Review
Chronic inflammation is known to be associated with enhanced production of both nitric oxide (NO) and reactive oxygen species such as superoxide (O2-) and hydrogen peroxide (H2O2). Patients with long-standing ulcerative colitis are also known to be at increased risk of developing colorectal cancer. Although NO and reactive oxygen intermediates alone have been known to damage DNA and to promote a wide array of mutagenic reactions, there is increasing evidence to suggest that the interaction between O2- and NO may dictate the type of mutagenic reactions produced at sites where both these free radicals are produced. In the absence of O2-, NO will engage in nitrosative chemistry to yield stable N-nitrosamine derivatives of secondary amines and promote nitrosative deamination of DNA bases. As the flux of O2- is increased, nitrosation reactions are suppressed and oxidative chemistry is enhanced. Thus, depending upon the fluxes of each radical either nitrosation or oxidation chemistry may predominate. The fundamental understanding between O2- and NO may provide new insight in the mechanisms responsible for inflammation-induced mutagenesis.
Topics: DNA Damage; Humans; Inflammation; Mutagenesis; Neoplasms; Nitric Oxide; Nitrosamines; Nitrosation; Oxidation-Reduction; Superoxides
PubMed: 9206981
DOI: 10.2741/a182 -
Japanese Journal of Infectious Diseases Oct 2004Myeloperoxidase (MPO) uses hydrogen peroxide to oxidize chloride to hypochlorous acid. It also converts numerous substrates to reactive free radicals. When released by... (Review)
Review
Myeloperoxidase (MPO) uses hydrogen peroxide to oxidize chloride to hypochlorous acid. It also converts numerous substrates to reactive free radicals. When released by neutrophils, the enzyme operates in the presence of a flux of superoxide. We show that superoxide has a profound influence on oxidative reactions catalysed by MPO. It reacts directly with the enzyme to modulate production of hypochlorous acid. Within neutrophil phagosomes, where MPO functions to kill micro-organisms, it may be the preferred substrate for the enzyme. Superoxide also reacts rapidly with radicals generated by MPO, e.g. from tyrosine and tyrosyl peptides. Initial products are organic peroxides. These species are likely to be toxic and contribute to the pathophysiological actions of MPO.
Topics: Animals; Molecular Structure; Oxidation-Reduction; Peroxidase; Superoxides
PubMed: 15507767
DOI: No ID Found -
Methods in Molecular Biology (Clifton,... 2022Intracellular reactive oxygen species (ROS) act as an important signaling transductor in cells, regulating almost every aspect of cell biology. Measurements of ROS...
Intracellular reactive oxygen species (ROS) act as an important signaling transductor in cells, regulating almost every aspect of cell biology. Measurements of ROS production thus, offer links between oxidative stress and cell pathophysiology. Here, we describe a simple screening assay in intact adherent cells by fluorescence microplate readers, using dihydroethidium (DHE) and MitoSOX to measure cytosolic superoxide and mitochondrial superoxide production, respectively. This assay enables a quick and reliable assessment of ROS generation in a well-controlled environment.
Topics: Ethidium; Oxidative Stress; Phenanthridines; Reactive Oxygen Species; Superoxides
PubMed: 35771455
DOI: 10.1007/978-1-0716-2309-1_24 -
Journal of Physiology and Pharmacology... Dec 2003Nitric oxide (NO) and reactive oxygen species exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses. They affect... (Review)
Review
Nitric oxide (NO) and reactive oxygen species exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses. They affect virtually every step of the development of inflammation. Low concentrations of nitric oxide produced by constitutive and neuronal nitric oxide synthases inhibit adhesion molecule expression, cytokine and chemokine synthesis and leukocyte adhesion and transmigration. Large amounts of NO, generated primarily by iNOS can be toxic and pro-inflammatory. Actions of nitric oxide are however not dependent primarily on the enzymatic source, but rather on the cellular context, NO concentration (dependent on the distance from NO source) and initial priming of immune cells. These observations may explain difficulties in determining the exact role of NO in Th1 and Th2 lymphocyte balance in normal immune responses and in allergic disease. Similarly superoxide anion produced by NAD(P)H oxidases present in all cell types participating in inflammation (leukocytes, endothelial and other vascular cells etc) may lead to toxic effects, when produced at high levels during oxidative burst, but may also modulate inflammation in a far more discrete way, when continuously produced at low levels by NOXs (non-phagocytic oxidases). The effects of both nitric oxide and superoxide in immune regulation are exerted through multiple mechanisms, which include interaction with cell signalling systems like cGMP, cAMP, G-protein, JAK/STAT or MAPK dependent signal transduction pathways. They may also lead to modification of transcription factors activity and in this way modulate the expression of multiple other mediators of inflammation. Moreover genetic polymorphisms exist within genes encoding enzymes producing both NO and superoxide. The potential role of these polymorphisms in inflammation and susceptibility to infection is discussed. Along with studies showing increasing role of NO and free radicals in mediating inflammatory responses drugs which interfere with these systems are being introduced in the treatment of inflammation. These include statins, angiotensin receptor blockers, NAD(P)H oxidase inhibitors, NO-aspirin and others. In conclusion in this mini-review we discuss the mechanisms of nitric oxide and superoxide dependent modulation of inflammatory reactions in experimental animals and humans. We also discuss potential roles of nitric oxide as a mediator of allergic inflammation.
Topics: Animals; Humans; Inflammation; Inflammation Mediators; Models, Biological; Nitric Oxide; Signal Transduction; Superoxides
PubMed: 14726604
DOI: No ID Found -
Journal of Agricultural and Food... Mar 2023The reactivity of 5-[()-2-(4-hydroxyphenyl)ethen-1-yl]benzene-1,3-diol (-resveratrol) and related compounds toward electrogenerated superoxide radical anion (O) were...
The reactivity of 5-[()-2-(4-hydroxyphenyl)ethen-1-yl]benzene-1,3-diol (-resveratrol) and related compounds toward electrogenerated superoxide radical anion (O) were investigated using electrochemistry, in situ electrolytic electron spin resonance, and in situ electrolytic ultraviolet-visible spectral measurements, in ,-dimethylformamide (DMF) with the aid of density functional theory (DFT) calculations. The quasi-reversible cyclic voltammogram of dioxygen/O was modified by the presence of -resveratrol, suggesting that the electrogenerated O was scavenged by -resveratrol through proton-coupled electron transfer (PCET) via three phenolic hydroxy groups (OH) on the stilbene moiety. The reactivity of -resveratrol toward O characterized by the OHs was experimentally confirmed in comparative analyses using some related compounds, pinosylvin, pterostilbene, -coumaric acid, and so on, in DMF. The electrochemical and DFT results suggested that a concerted PCET mechanism via 4'OH of -resveratrol proceeds, where the coplanarity of the two phenolic rings in the stilbene moiety linked by an ethylene bridge is essential for a successful O scavenging.
Topics: Resveratrol; Superoxides; Dimethylformamide; Antioxidants; Stilbenes
PubMed: 36852964
DOI: 10.1021/acs.jafc.2c08105 -
Biochimica Et Biophysica Acta Feb 2010Superoxide anion is among the deleterious reactive oxygen species, towards which all organisms have specialized detoxifying enzymes. For quite a long time, superoxide... (Review)
Review
Superoxide anion is among the deleterious reactive oxygen species, towards which all organisms have specialized detoxifying enzymes. For quite a long time, superoxide elimination was thought to occur through its dismutation, catalyzed by Fe, Cu, and Mn or, as more recently discovered, by Ni-containing enzymes. However, during the last decade, a novel type of enzyme was established that eliminates superoxide through its reduction: the superoxide reductases, which are spread among anaerobic and facultative microorganisms, from the three life kingdoms. These enzymes share the same unique catalytic site, an iron ion bound to four histidines and a cysteine that, in its reduced form, reacts with superoxide anion with a diffusion-limited second order rate constant of approximately 10(9) M(-1) s(-1). In this review, the properties of these enzymes will be thoroughly discussed.
Topics: Amino Acid Sequence; Animals; Humans; Molecular Sequence Data; Oxidoreductases; Sequence Homology, Amino Acid; Superoxides
PubMed: 19857607
DOI: 10.1016/j.bbapap.2009.10.011 -
Photochemistry and Photobiology 1978
Review
Topics: Aerobiosis; Animals; Cell Survival; Enzyme Induction; Escherichia coli; Free Radicals; Metabolism; Oxidation-Reduction; Oxygen; Oxygen Consumption; Superoxide Dismutase; Superoxides
PubMed: 216032
DOI: 10.1111/j.1751-1097.1978.tb07009.x -
Methods (San Diego, Calif.) Oct 2016Detection of superoxide produced by living cells has been an on-going challenge in biology for over forty years. Various methods have been proposed to address this... (Review)
Review
Detection of superoxide produced by living cells has been an on-going challenge in biology for over forty years. Various methods have been proposed to address this issue, among which spin trapping with cyclic nitrones coupled to EPR spectroscopy, the gold standard for detection of radicals. This technique is based on the nucleophilic addition of superoxide to a diamagnetic cyclic nitrone, referred to as the spin trap, and the formation of a spin adduct, i.e. a persistent radical with a characteristic EPR spectrum. The first application of spin trapping to living cells dates back 1979. Since then, considerable improvements of the method have been achieved both in the structures of the spin traps, the EPR methodology, and the design of the experiments including appropriate controls. Here, we will concentrate on technical aspects of the spin trapping/EPR technique, delineating recent breakthroughs, inherent limitations, and potential artifacts.
Topics: Electron Spin Resonance Spectroscopy; Free Radicals; Nitrogen Oxides; Spin Labels; Spin Trapping; Superoxides
PubMed: 27163864
DOI: 10.1016/j.ymeth.2016.05.001