Reactive intermediates quinones. Medical search. Frequent questions

Enzymes like monoamine oxidase (MAO) can oxidize dopamine, leading to the formation of reactive intermediates such as quinones and reactive oxygen species. (thesciencenotes.com)
DA is unstable and can undergo oxidation and metabolism to produce multiple reactive and toxic by-products, including reactive oxygen species, DA quinones, and 3,4-dihydroxyphenylacetaldehyde. (biomedcentral.com)
The effects of sulforaphane on multiple pathways of biochemical dysfunction, increased reactive oxygen species (ROS) formation, hexosamine pathway, protein kinase C (PKC) pathway, and increased formation of methylglyoxal were assessed. (diabetesjournals.org)
48], Superoxide is a reactive oxygen species that contributes to cellular oxidative stress and is linked to neuromuscular diseases and aging. (gowebamerica.com)
It is also a major contributor to cellular production of reactive oxygen species. (gowebamerica.com)
Complex I has also been suggested to be a major source of reactive oxygen species in mitochondria, which can damage mitochondrial DNA and may be one of the causes of Parkinson's disease and ageing. (mpg.de)
This research paper will focus on the underlying mechanisms of cancer development related to the consumption of processed foods, specifically by highlighting the production of reactive oxygen species (ROS), which are unstable molecules containing oxygen that can easily damage cells. (nhsjs.com)
Excessive reactive oxygen species (ROS), which encompass highly reactive molecules such as hydroxyl radicals (OH-), superoxide radicals (O2-), and hydrogen peroxide (H2O2), act as oxidants. (nhsjs.com)
The primary goal of this paper is to discuss how processed food intake generates reactive oxygen species that can increase the risk of oncogenesis, with a focus on foods that contain a significant number of nitrites and nitrate, additives, polyaromatic hydrocarbons, heterocyclic amines, trans fats, and sugar. (nhsjs.com)
The iron gall ink-triggered chemical corrosion of hand-written documents is a big threat to Western cultural heritages, which was demonstrated to result from the iron gall (GA-Fe) chelate-promoted reactive oxygen species generation. (nature.com)
Therefore, the ion centers act as active sites of the metallo-gallate complex that can donate electrons from the gallate ligands to ambient free oxygen molecules for the oxygen reduction and reactive oxygen species (ROS) generation 3 , after which the ligand field around iron center attenuates due to the electron loss from gallate 12 . (nature.com)
Reactive oxygen species are reactive molecules that play a role in cellular signaling and are formed as side products in physiological processes. (5dok.net)
Many external factors are implicated with carcinogenesis, one of which are reactive oxygen species. (5dok.net)

Alcohol dehydrogenase (ADH) contributes significantly to NADH-dependent C-nitroso reduction by cytosol relative to NAD(P)H: quinone oxidoreductase (NQOR). (lsu.edu)
NAD(P)H:quinone acceptor oxidoreductase 1 (NQO1) is a widely-distributed FAD-dependent flavoprotein that promotes obligatory 2-electron reductions of quinones, quinoneimines, nitroaromatics, and azo dyes, at rates that are comparable with NADH or NADPH. (dundee.ac.uk)

These partially ionized gases deliver a therapeutic cocktail of reactive oxygen and nitrogen species safely at body temperature and without genotoxic side effects. (mdpi.com)
For example, they imaged the protonation/deprotonation state (related to the pH) of sites within the enzyme that are important for stabilizing radical species (i.e., especially reactive atoms that contain an unpaired electron). (sciencedaily.com)

These reductions depress quinone levels and thereby minimize opportunities for generation of reactive oxygen intermediates by redox cycling, and for depletion of intracellular thiol pools. (dundee.ac.uk)
12][13], The equilibrium dynamics of Complex I are primarily driven by the quinone redox cycle. (gowebamerica.com)
14], The coupling of proton translocation and electron transport in Complex I is currently proposed as being indirect (long range conformational changes) as opposed to direct (redox intermediates in the hydrogen pumps as in heme groups of Complexes III and IV). (gowebamerica.com)
Cytochromes P450 monooxygenases represent a large superfamily of heme enzymes, which require a dioxygen molecule and two electrons supplied by a NAD(P)H-dependent protein redox partner to form catalytically active high-valent ferryl-oxo intermediate. (schoolbag.info)
The iron serves as a sole redox center in the catalytic cycle, which accepts two electrons sequentially and channels them to coordinated dioxygen to form a (hydro)peroxo-ferric intermediate. (schoolbag.info)

Graduate research activities involving mechanistic studies on xenobiotic toxicity invariably expose students to the field of drug metabolism, particularly in cases where xenobiotics are enzymatically bioactivated to electrophilic reactive metabolites that can covalently adduct to proteins and DNA and cause toxicity. (aspetjournals.org)
The liver serves an important function in benzene metabolism, which results in the production of several reactive metabolites. (europa.eu)

DFs release the quinone imine and free H2 O2 in the oxidation of 4-aminophenol in the presence of O2 , whereas Fe(III) -DF-C1 sequesters the quinone imine into the active site, and catalyzes inside the scaffold an oxidative coupling between oxidized and reduced 4-aminophenol. (cnr.it)
Despite the unprecedented variability of chemical reactions catalyzed by cytochromes P450, all the important features of their mechanism can be attributed to the oxidative transformations driven by the main catalytic intermediate, which is a ferryl-oxo heme complex with the porphyrin pi-cation radical, or Compound I (3, 4, 8). (schoolbag.info)

Complex I is the first enzyme of the respiratory chain and has a central role in cellular energy production, coupling electron transfer between NADH and quinone to proton translocation by an unknown mechanism. (mpg.de)

After the primary coupling of two phenoxy radicals a very reactive quinone methide intermediate is formed. (vtt.fi)
Recent studies suggested that long-lived photooxidants (LLPO), which are reactive intermediates formed during irradiation of dissolved organic matter (DOM), may consist of phenoxyl radicals derived from phenolic moieties of the DOM. (eawag.ch)

The structural aspects and important functional groups of several classes of molecules that have been found to impart mechanism-based inactivation upon metabolism by P450s such as acetylenes, thiol-containing compounds that include isothiocyanates, thiazolidinediones, and thiophenes, arylamines, quinones, furanocoumarins, and cyclic tertiary amines are described. (johnshopkins.edu)

C-nitroso compounds are reactive intermediates in the toxic sequelae of nitroarene metabolism. (lsu.edu)
Cytochrome P450 1B1 (CYP1B1) is active in the metabolism of estrogens to reactive catechols and of different procarcinogens. (biomedcentral.com)

Suwannee River fulvic acid (SRFA) as a model DOM was pre-oxidised using the phenol-reactive oxidants chlorine and ozone, followed by its characterization by the specific UV absorption at 254 nm (SUVA 254 ), the ratio of absorbance at λ = 254 nm and λ = 365 nm (E2:E3), and the electron donating capacity (EDC). (eawag.ch)

Although P450-catalyzed reactions are generally thought to lead to detoxication of xenobiotics, the reactions can also produce reactive intermediates that can react with cellular macromolecules leading to toxicity or that can react with the P450s that form them leading to irreversible (i.e., mechanism-based) inactivation. (johnshopkins.edu)

Cytochromes P450 represent a superfamily of heme enzymes with a common fold and mechanism that requires an atmospheric dioxygen molecule, two electrons from NAD(P)H, and one or two protons available from solvent water to form an active catalytic ferryl-oxo intermediate (1). (schoolbag.info)
Most reactions performed by cytochromes P450 can be catalyzed effectively by Compound I, which is formally the same high-valent intermediate in all isozymes (5, 6). (schoolbag.info)

We previously reported the utility of a nitrobenzenethiol (NBT) binding assay for screening thiol reactive haptens (Chipinda et al Chem. (cdc.gov)

As a result, only a pyrimidine analog of NVP, which could avoid the formation of a reactive epoxide intermediate, did not inhibit CYP3A4. (unboundmedicine.com)
It is formed as an intermediate during the formation of norepinephrine and epinephrine [ 20 ]. (biomedcentral.com)
Second protonation of the distal oxygen atom and transient formation of the iron coordinated oxo-water, Fe-OOH 2 , results in the heterolytic scission of O-O bond and formation of the ferryl oxo porphyrin-cation radical, which is termed Compound I, by analogy to the same active intermediate first documented in peroxidases and catalases (2). (schoolbag.info)

Outside of this compound, the other synthesized compounds, which could avoid the generation of a reactive quinone-methide intermediate, inhibited CYP3A4 equal to or stronger than NVP. (unboundmedicine.com)
Originally discovered by Sodeoka 25 years ago, they readily form reactive chiral Pd enolates upon deprotonation of b-dicarbonyl compounds and simultaneously, a Brønsted acid liberated from the catalyst activates the electrophile. (uni-leipzig.de)

Emphasis throughout this perspective is placed on more recent findings with human P450s where the site of modification, whether it be the apoprotein or the heme moiety, and, at least in part, the identity of the reactive intermediate responsible for the loss in P450 activity are known or inferred. (johnshopkins.edu)

There are pH-dependence, conformational change, and radical intermediate stabilization questions of our enzyme that X-ray crystallography in itself cannot fully explain," explains Takeshi Murakawa, lead author of the study. (sciencedaily.com)

After the nucleophilic addition to the quinone methide, other hydrolytic reactions, rearrangements, and elimination reactions occur, leading finally to stable dimeric structures called lignans or dilignols. (vtt.fi)

Substrate binding at the distal site of the heme brings the target chemical group into the close proximity of the reactive iron-oxygen catalytic intermediate, often in the regiospecific and stereospecific mode, to provide the selectivity of the chemical transformation. (schoolbag.info)

Among these, the citric acid cycle intermediate succinate stands out owing to its multiple roles in disparate pathways, its dramatic concentration changes and its selective cell release. (nature.com)

These results indicated that the epoxide intermediate of NVP might play an important role in NVP-induced liver injury. (unboundmedicine.com)

Furthermore, the structure of a complex I assembly intermediate and mutant (structure solved at 4.0 Å resolution) provide detailed molecular insights into complex I assembly and the cause of a hereditary complex I-linked disease, which has been shown to cause the Leigh's disease in humans with various types of mutations. (mpg.de)

Formation of BHT-quinone methide via a chemical-chemical interaction. (nih.gov)
Moreover, in the presence of BHA, the formation of the polar and aqueous metabolites of BHT was increased and two additional metabolites, BHT-quinone methide and stilbenequinone, were detected. (nih.gov)
the PNA part (peptide nucleic acids) ensures sequence specific hybridization with the target and the quinone methide (highlighted in yellow) as a potent electrophile reversibly alkylates nucleophilic sites within the RNA (RNA nucleotides shown in black, PNA nucleotides in magenta). (uni-frankfurt.de)
They must be formed from appropriate precursors directly before use (QMP: quinone methide precursor). (uni-frankfurt.de)
In a second approach, we have investigated the activation of quinone methide precursors 2 - 4 by redox reactions. (uni-frankfurt.de)
The oxidative transformation of curcumin is rapid, prominent, and gives rise to novel metabolites via reactive intermediates, including a quinone methide and a spiro-epoxide intermediate. (nih.gov)
Specifically, we will analyze the mechanism of inhibition of reduced and oxidized IKKß by electrophilic and nucleophilic curcumin metabolites, the mechanism of induction of DNA cleavage by topoisomerase II, and protein and DNA adduct formation by the quinone methide intermediate. (nih.gov)
3. LC-MS/MS reveals the formation of iminium and quinone methide reactive intermediates in entrectinib metabolism: In vivo and in vitro metabolic investigation. (nih.gov)
These results demonstrate that eugenol is actively metabolized in hepatocytes and suggest that the cytotoxic effects of eugenol are due to the formation of a reactive intermediate, possibly a quinone methide. (nih.gov)
Acidic conditions favored the reaction of quinone methide intermediates with carboxyl groups of glucuronic acid in the biosynthesis of DHP. (ncsu.edu)
However, weakly acidic conditions (pH 6) enhanced the reaction of quinone methide intermediates with glucose. (ncsu.edu)
In neutral conditions, the DHP-protein complex can be efficiently synthesized by the addition reaction of quinone methide intermediates with amino acids in protein. (ncsu.edu)
Erben, A., Sviben, I., Mihaljević, B., Piantanida, I. & Basarić, N. (2021) Non-Covalent Binding of Tripeptides-Containing Tryptophan to Polynucleotides and Photochemical Deamination of Modified Tyrosine to Quinone Methide Leading to Covalent Attachment . (irb.hr)
2001). It has been suggested that a possible mechanism of troglitazone-induced hepatotoxicity in humans could involve its metabolism to a toxic quinone-metabolite, which can be further metabolized to an o-quinone methide to produce additional highly electrophilic intermediates. (bcl2-receptor.com)

Quinone methides, however, are labile intermediates that cannot be kept in stock. (uni-frankfurt.de)
The effect of pH on the addition reaction of glucuronic acid to quinone methides generated in the synthesis of dehydrogenation polymer (DHP or artificial lignin) was investigated. (ncsu.edu)
and nucleophilic addition reaction of quinone methides with nucleophiles during polymerization (Sarkanen and Ludwig 1971). (ncsu.edu)

In Specific Aim 2 we will identify the products and intermediates of oxidative transformation of curcumin and determine their mechanism of formation. (nih.gov)
To assess whether or not the anti SFV results of PO have been as a result of formation of reactive intermediates or other solutions formed by PO, we infected U4. (agckinases.com)
We also propose that a hydrophobic tunnel forms between the two active sites of the complex and propose that this tunnel shuttles the reactive hydroxyl intermediate, thus preventing the formation of the non-enzymatic end product. (illinois.edu)
Secondary damage is from the formation of highly reactive products generated from the ionization of protein atoms and the photolysis of water that then further interact with the sample. (iucr.org)

Preliminary assessment suggests labile reactive intermediates are formed during PDA reaction to quinones and benzyl bromide. (cdc.gov)

It is anticipated that HyperCys will be an effective tool for discovering new potential reactive cysteines in a wide range of nucleophilic proteins and will provide an important contribution to the design of targeted covalent inhibitors with high potency and selectivity. (uni-freiburg.de)
The emphasis is on those reactions that give different product distributions on the potential reactive sites inside the containers than they do outside, free in solution. (beilstein-journals.org)
To run reactions with discriminate control over product selectivity represents one of the huge challenges in organic synthetic chemistry [1] , among which, site-selectivity is always crucial to a reaction when there is more than one potential reactive site in a certain substrate, because poor site-selectivity would result in complicated and sometimes even unachievable separation and purification procedures. (beilstein-journals.org)

Ex- Alcohols, aldehydes, quinones are reduced. (slideshare.net)

Quinones and phenolic radicals are also intermediates in the biosynthesis of macromolecular structures (lignins and melanins) generated by plants and insects in response to pathogen attack. (usda.gov)
An intermediate of tricarboxylic acid cycle alpha-ketoglutarate (AKG) is involved in pleiotropic metabolic and regulatory pathways in the cell, including energy production, biosynthesis of certain amino acids, collagen biosynthesis, epigenetic regulation of gene expression, regulation of redox homeostasis, and detoxification of hazardous substances. (preventivehealth.blog)

Whereas there remains much to learn about the potential biological relevance of UGTs, deficient glucuronidation can result in either elevated tissue concentrations and direct toxicity of substrates, as with the endobiotic bilirubin, or, alternatively, enhanced bioactivation of substrates to toxic reactive intermediates, as in the case of acetaminophen and benzo[ a ]pyrene. (aspetjournals.org)

There is a putative class II aldolase, PluG, in the biosynthetic pathway which is proposed to catalyze an aldol reaction between oxaloacetate and phosphonoacetaldehyde to form a reactive hydroxyl intermediate (2-keto-4-hydroxy-5-phosphonopentanoic acid), with a chance to form an irreversible, non-enzymatic dehydration reaction which forms an off pathway end product. (illinois.edu)
Trans-silylation reaction with methyltrichlorosilane yields Si-C-N ceramic intermediate. (gelest.com)
i) a decline in the total N denitrified (with less N 2 O emitted from soil in the intermediate reaction) or (ii) an enhancement of its further reduction to N 2 . (nature.com)

The latter is cleaved by -lyase to form 1,2-dichlorovinylthiol, a reactive intermediate which is implicated in covalent modification of proteins and other cel- lular targets. (wgc2010.sk)

Objective: Modified C-reactive protein (mCRP) is known to be involved in the upregulation and amplification of the local inflammatory response. (bvsalud.org)

Alcohol dehydrogenase (ADH) contributes significantly to NADH-dependent C-nitroso reduction by cytosol relative to NAD(P)H: quinone oxidoreductase (NQOR). (lsu.edu)
Summary Over the last several years, intermediates in the reduction of dioxygen have been attributed diverse functional roles ranging from protection against pathogen attack to the regulation of cellular development. (dadospdf.com)

The redox activity of quinones is integral to their physiological function in the electron transfer pathways of respiration and photosynthesis. (usda.gov)

Upon irradiation, however, the nitrobenzyl group is cleaved off and subsequent elimination of acetic acid liberates the reactive intermediate 5 . (uni-frankfurt.de)

Clearly, the role of ROS in both plant defense and other physiological responses complicates any models that employ these intermediates in host plant recognition. (dadospdf.com)

This approach enabled us to provide the first in vivo evidence that a conserved noncatalytic domain of WRN helicase plays a critical role in facilitating the processing of DNA structural intermediates that arise during replication. (nih.gov)
Compared to traditional ML models with only sequenced-based features or only 3D structural features, HyperCys is more accurate at predicting hyper-reactive druggable cysteines. (uni-freiburg.de)

On the other hand, hydroquinone can be a component of high molecular aromatic compounds (e.g., resin), an intermediate, or appear as a degradation product generated by transformation of aromatic compounds. (hindawi.com)

Now, in a study titled "Neutron crystallography of a semiquinone radical intermediate of copper amine oxidase reveals a substrate-assisted conformational change of the peptidyl quinone cofactor," published in ACS Catalysis , a team led by researchers at Osaka Medical and Pharmaceutical University and Osaka University has used neutron crystallography to image the atom-by-atom structure of a copper amine oxidase enzyme. (phys.org)
Takeshi Murakawa et al, Neutron Crystallography of a Semiquinone Radical Intermediate of Copper Amine Oxidase Reveals a Substrate-Assisted Conformational Change of the Peptidyl Quinone Cofactor, ACS Catalysis (2023). (phys.org)

There is a strong genotoxic mechanism for carcinogenicity of several AAs, and multiple metabolic pathways as well as many polymorphic genes have been found to be implicated in the activation of AAs into DNA-reactive intermediates [ 10 ]. (biomedcentral.com)
I will pursue three lines of research within the theme of oxidant stress-mediated effects on cell growth: NADPH oxidase 1, the glutathione peroxidase gene family, and the mechanism of action of anticancer quinones. (nih.gov)

Meanwhile, in the oxidative degradation of hydroquinone under a supercritical condition (409.9°C and 24.5 MPa) and subcritical condition (359.9°C and 24.5 MPa), -benzoquinone was to be an important intermediate [ 3 ]. (hindawi.com)

The peroxidase-dependent activation of butylated hydroxyanisole and butylated hydroxytoluene (BHT) to reactive intermediates. (nih.gov)

0R and additional GSH, which as mentioned over likely inhibits melanisation by cutting down quinones. (agckinases.com)

Acute or chronic nongranulomatous anterior uveitis occurs in reactive arthritis in as many as 30% of cases. (medscape.com)

Synthesis and Structure of Metalloid Aluminum Clusters - Intermediates on the Way to the Elements. (mit.edu)
Structure of semiquinone radical intermediate. (phys.org)
HyperCys: A Structure- and Sequence-Based Predictor of Hyper-Reactive Druggable Cysteines. (uni-freiburg.de)

Hence, to identify targetable cysteines, we propose a novel ensemble stacked machine learning (ML) model to predict hyper-reactive druggable cysteines, named HyperCys. (uni-freiburg.de)

We have discovered that BACH1 preferentially unwinds specific early DNA recombination intermediates of double-strand break repair, providing new insights into the DNA substrate specificity of BACH1. (nih.gov)

Anatomy8

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