Cytochrome reductases are enzymes that catalyze the transfer of electrons from donor molecules to cytochromes in electron transport chains, playing a crucial role in cellular respiration and energy production within cells.
A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.
A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)
Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.
Cytochromes (electron-transporting proteins) with protoheme (HEME B) as the prosthetic group.
Cytochromes of the c type that are found in eukaryotic MITOCHONDRIA. They serve as redox intermediates that accept electrons from MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX III and transfer them to MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX IV.
Cytochromes of the b group that are found bound to cytoplasmic side of ENDOPLASMIC RETICULUM. They serve as electron carrier proteins for a variety of membrane-bound OXYGENASES. They are reduced by the enzyme CYTOCHROME-B(5) REDUCTASE.
Oxidoreductases that are specific for the reduction of NITRATES.
A flavoprotein that catalyzes the reduction of heme-thiolate-dependent monooxygenases and is part of the microsomal hydroxylating system. EC 1.6.2.4.
A FLAVOPROTEIN oxidoreductase that occurs both as a soluble enzyme and a membrane-bound enzyme due to ALTERNATIVE SPLICING of a single mRNA. The soluble form is present mainly in ERYTHROCYTES and is involved in the reduction of METHEMOGLOBIN. The membrane-bound form of the enzyme is found primarily in the ENDOPLASMIC RETICULUM and outer mitochondrial membrane, where it participates in the desaturation of FATTY ACIDS; CHOLESTEROL biosynthesis and drug metabolism. A deficiency in the enzyme can result in METHEMOGLOBINEMIA.
Enzymes that catalyze the reversible reduction of alpha-carboxyl group of 3-hydroxy-3-methylglutaryl-coenzyme A to yield MEVALONIC ACID.
A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.
The 30-kDa membrane-bound c-type cytochrome protein of mitochondria that functions as an electron donor to CYTOCHROME C GROUP in the mitochondrial and bacterial RESPIRATORY CHAIN. (From Enzyme Nomenclature, 1992, p545)
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
Ribonucleotide Reductases are enzymes that catalyze the conversion of ribonucleotides to deoxyribonucleotides, which is a crucial step in DNA synthesis and repair, utilizing a radical mechanism for this conversion.

Cloning and characterization of a maize cytochrome-b5 reductase with Fe3+-chelate reduction capability. (1/395)

We previously purified an NADH-dependent Fe3+-chelate reductase (NFR) from maize roots with biochemical features of a cytochrome-b5 reductase (b5R) [Sparla, Bagnaresi, Scagliarini and Trost (1997) FEBS Lett. 414, 571-575]. We have now cloned a maize root cDNA that, on the basis of sequence information, calculated parameters and functional assay, codes for NFR. Maize NFR has 66% and 65% similarity to mammal and yeast b5R respectively. It has a deduced molecular mass of 31.17 kDa and a pI of 8.53. An uncharged region is observed at its N-terminus but no myristoylation consensus site is present. Taken together, these results, coupled with previous biochemical evidence, prove that NFR belongs to the b5R class and document b5R from a plant at the molecular level for the first time. We have also identified a putative Arabidopsis thaliana NFR gene. Its organization (nine exons) closely resembles mammalian b5Rs. Several NFR isoforms are expected to exist in maize. They are probably not produced by alternative translational mechanisms as occur in mammals, because of specific constraints observed in the maize NFR cDNA sequence. In contrast with yeast and mammals, tissue-specific and various subcellular localizations of maize b5R isoforms could result from differential expression of the various members of a multigene family. The first molecular characterization of a plant b5R indicates an overall remarkable evolutionary conservation for these versatile reductase systems. In addition, the well-characterized Fe3+-chelate reduction capabilities of NFR, in addition to known Fe3+-haemoglobin reduction roles for mammal b5R isoforms, suggest further and more generalized roles for the b5R class in endocellular iron reduction.  (+info)

Purification of gibberellic acid-induced lysosomes from wheat aleurone cells. (2/395)

Using isopycnic density gradient centrifugation, lysosomes were concentrated in a single region of a sucrose-Ficoll gradient (p = 1-10 g cm-3), well separated from most other cell organelles. Gibberellic acid-induced lysosomes were found to be rich in alpha-amylase and protease but not ribonuclease. The lysosomal band also contained a majority of the NADH2-cytochrome c reductase, a marker enzyme for endoplasmic reticulum, found in the gradient. Examination of electron micrographs revealed that a purified band of lyosomes contained at least 3 vesicle types, ranging in size from 0-1 to 0-5 mum. The significance of these findings to proposed mechanisms of action of gibberellic acid is discussed.  (+info)

Phospholipid requirement for dimethylnitrosamine demethylation by hamster hepatic microsomal cytochrome P-450 enzyme system. (3/395)

Extraction with butan-1-ol of freeze-dried microsomal fractions from livers of 3-methyl-cholarthrene-pre-treated hamsters removed about 90% of the total lipid content, but the lipid remaining proved sufficient for the cytochrome P-450 enzyme system to retain about 15-40% of its original catalytic activity for dimethylnitrosamine demethylation. Addition of butan-1-ol-extracted total phospholipid or phosphatidylcholine could not restore any activity, whereas the addition of the synthetic phospholipid dilauroyl phosphatidylcholine was able to restore almost complete activity. Synthetic dipalmitoyl or distearoyl phosphatidylcholine was ineffective in restoring the activity in this reconstituted system.  (+info)

Targeting proteins to the lumen of endoplasmic reticulum using N-terminal domains of 11beta-hydroxysteroid dehydrogenase and the 50-kDa esterase. (4/395)

Previous studies identified two intrinsic endoplasmic reticulum (ER) proteins, 11beta-hydroxysteroid dehydrogenase, isozyme 1 (11beta-HSD) and the 50-kDa esterase (E3), sharing some amino acid sequence motifs in their N-terminal transmembrane (TM) domains. Both are type II membrane proteins with the C terminus projecting into the lumen of the ER. This finding implied that the N-terminal TM domains of 11beta-HSD and E3 may constitute a lumenal targeting signal (LTS). To investigate this hypothesis we created chimeric fusions using the putative targeting sequences and the reporter gene, Aequorea victoria green fluorescent protein. Transfected COS cells expressing LTS-green fluorescent protein chimeras were examined by fluorescent microscopy and electron microscopic immunogold labeling. The orientation of expressed chimeras was established by immunocytofluorescent staining of selectively permeabilized COS cells. In addition, protease protection assays of membranes in the presence and absence of detergents was used to confirm lumenal or the cytosolic orientation of the constructed chimeras. To investigate the general applicability of the proposed LTS, we fused the N terminus of E3 to the N terminus of the NADH-cytochrome b5 reductase lacking the myristoyl group and N-terminal 30-residue membrane anchor. The orientation of the cytochrome b5 reductase was reversed, from cytosolic to lumenal projection of the active domain. These observations establish that an amino acid sequence consisting of short basic or neutral residues at the N terminus, followed by a specific array of hydrophobic residues terminating with acidic residues, is sufficient for lumenal targeting of single-pass proteins that are structurally and functionally unrelated.  (+info)

Identification of an NADH-cytochrome b(5) reductase gene from an arachidonic acid-producing fungus, Mortierella alpina 1S-4, by sequencing of the encoding cDNA and heterologous expression in a fungus, Aspergillus oryzae. (5/395)

Based on the sequence information for bovine and yeast NADH-cytochrome b(5) reductases (CbRs), a DNA fragment was cloned from Mortierella alpina 1S-4 after PCR amplification. This fragment was used as a probe to isolate a cDNA clone with an open reading frame encoding 298 amino acid residues which show marked sequence similarity to CbRs from other sources, such as yeast (Saccharomyces cerevisiae), bovine, human, and rat CbRs. These results suggested that this cDNA is a CbR gene. The results of a structural comparison of the flavin-binding beta-barrel domains of CbRs from various species and that of the M. alpina enzyme suggested that the overall barrel-folding patterns are similar to each other and that a specific arrangement of three highly conserved amino acid residues (i.e., arginine, tyrosine, and serine) plays a role in binding with the flavin (another prosthetic group) through hydrogen bonds. The corresponding genomic gene, which was also cloned from M. alpina 1S-4 by means of a hybridization method with the above probe, had four introns of different sizes. These introns had GT at the 5' end and AG at the 3' end, according to a general GT-AG rule. The expression of the full-length cDNA in a filamentous fungus, Aspergillus oryzae, resulted in an increase (4.7 times) in ferricyanide reduction activity involving the use of NADH as an electron donor in the microsomes. The M. alpina CbR was purified by solubilization of microsomes with cholic acid sodium salt, followed by DEAE-Sephacel, Mono-Q HR 5/5, and AMP-Sepharose 4B affinity column chromatographies; there was a 645-fold increase in the NADH-ferricyanide reductase specific activity. The purified CbR preferred NADH over NADPH as an electron donor. This is the first report of an analysis of this enzyme in filamentous fungi.  (+info)

Preparation of homogenous NADPH cytochrome c (P-450) reductase from house flies using affinity chromatography techniques. (6/395)

NADPH-cytochrome c (P-450) reductase (EC 1.6.2.4) was purified to apparent homogeneity from microsomes of house flies, Musca domestica L. The purification procedure involves column chromatography on three different resins. The key step in the purification scheme is the chromatography of the enzyme mixture on an affinity column of agarose-hexane-nicotinamide adenine dinucleotide phosphate. The enzyme has an estimated molecular weight of 83,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and contains 1 mol each of FAD and FMN per mol of enzyme. The enzyme exhibited a Bi Bi ping-pong kinetic mechanism with NADPH and cytochrome c. The Vmax and Km for cytochrome c were 42.3 mumol min-1 mg-1 and 12.7 muM, respectively. Turnover numbers based on micromoles of enzyme were 2,600 min-1. NADP+ and 2'-AMP both inhibited the reductases with apparent Ki values of 6.9 and 187 muM, respectively. These preparations of NADPH-cytochrome c reductase were found to reduce purified house fly cytochrome P-450 in the presence of NADPH.  (+info)

Adaptation of cytochrome-b5 reductase activity and methaemoglobinaemia in areas with a high nitrate concentration in drinking-water. (7/395)

An epidemiological investigation was undertaken in India to assess the prevalence of methaemoglobinaemia in areas with high nitrate concentration in drinking-water and the possible association with an adaptation of cytochrome-b5 reductase. Five areas were selected, with average nitrate ion concentrations in drinking-water of 26, 45, 95, 222 and 459 mg/l. These areas were visited and house schedules were prepared in accordance with a statistically designed protocol. A sample of 10% of the total population was selected in each of the areas, matched for age and weight, giving a total of 178 persons in five age groups. For each subject, a detailed history was documented, a medical examination was conducted and blood samples were taken to determine methaemoglobin level and cytochrome-b5 reductase activity. Collected data were subjected to statistical analysis to test for a possible relationship between nitrate concentration, cytochrome-b5 reductase activity and methaemoglobinaemia. High nitrate concentrations caused methaemoglobinaemia in infants and adults. The reserve of cytochrome-b5 reductase activity (i.e. the enzyme activity not currently being used, but which is available when needed; for example, under conditions of increased nitrate ingestion) and its adaptation with increasing water nitrate concentration to reduce methaemoglobin were more pronounced in children and adolescents.  (+info)

Apparent dependence of interactions between cytochrome b5 and cytochrome b5 reductase upon translational diffusion in dimyristoyl lecithin liposomes. (8/395)

Dimyristoyl lecithin liposomes, containing cytochrome b5 reductase (NADH:ferricytochrome b5 oxidoreductase, EC 1.6.2.2) and varying amounts of cytochrome b5, were used to measure flavoprotein catalysis alone and catalysis requiring electron transfer between the reductase and cytochrome as a function of temperature. Whereas flavoprotein catalysis showed a simple linear temperature dependence in an Arrhenius plot, the reaction involving electron transfer between the two bound enzymes showed a marked, 4-fold, change in rate at the crystalline-liquid crystalline phase transition of the hydrocarbon chains of the lecithin vesicles and a second, minor change involving the minor transition. These data represent strong evidence that protein-protein interactions in this membrane model system are dependent upon translational diffusion of nonpolar segments of the proteins in the hydrocarbon region of the phospholipid bilayer.  (+info)

Cytochrome reductases are a group of enzymes that play a crucial role in the electron transport chain, a process that occurs in the mitochondria of cells and is responsible for generating energy in the form of ATP (adenosine triphosphate). Specifically, cytochrome reductases are responsible for transferring electrons from one component of the electron transport chain to another, specifically to cytochromes.

There are several types of cytochrome reductases, including NADH dehydrogenase (also known as Complex I), succinate dehydrogenase (also known as Complex II), and ubiquinone-cytochrome c reductase (also known as Complex III). These enzymes help to facilitate the flow of electrons through the electron transport chain, which is essential for the production of ATP and the maintenance of cellular homeostasis.

Defects in cytochrome reductases can lead to a variety of mitochondrial diseases, which can affect multiple organ systems and may be associated with symptoms such as muscle weakness, developmental delays, and cardiac dysfunction.

The Cytochrome P-450 (CYP450) enzyme system is a group of enzymes found primarily in the liver, but also in other organs such as the intestines, lungs, and skin. These enzymes play a crucial role in the metabolism and biotransformation of various substances, including drugs, environmental toxins, and endogenous compounds like hormones and fatty acids.

The name "Cytochrome P-450" refers to the unique property of these enzymes to bind to carbon monoxide (CO) and form a complex that absorbs light at a wavelength of 450 nm, which can be detected spectrophotometrically.

The CYP450 enzyme system is involved in Phase I metabolism of xenobiotics, where it catalyzes oxidation reactions such as hydroxylation, dealkylation, and epoxidation. These reactions introduce functional groups into the substrate molecule, which can then undergo further modifications by other enzymes during Phase II metabolism.

There are several families and subfamilies of CYP450 enzymes, each with distinct substrate specificities and functions. Some of the most important CYP450 enzymes include:

1. CYP3A4: This is the most abundant CYP450 enzyme in the human liver and is involved in the metabolism of approximately 50% of all drugs. It also metabolizes various endogenous compounds like steroids, bile acids, and vitamin D.
2. CYP2D6: This enzyme is responsible for the metabolism of many psychotropic drugs, including antidepressants, antipsychotics, and beta-blockers. It also metabolizes some endogenous compounds like dopamine and serotonin.
3. CYP2C9: This enzyme plays a significant role in the metabolism of warfarin, phenytoin, and nonsteroidal anti-inflammatory drugs (NSAIDs).
4. CYP2C19: This enzyme is involved in the metabolism of proton pump inhibitors, antidepressants, and clopidogrel.
5. CYP2E1: This enzyme metabolizes various xenobiotics like alcohol, acetaminophen, and carbon tetrachloride, as well as some endogenous compounds like fatty acids and prostaglandins.

Genetic polymorphisms in CYP450 enzymes can significantly affect drug metabolism and response, leading to interindividual variability in drug efficacy and toxicity. Understanding the role of CYP450 enzymes in drug metabolism is crucial for optimizing pharmacotherapy and minimizing adverse effects.

Cytochrome c is a small protein that is involved in the electron transport chain, a key part of cellular respiration in which cells generate energy in the form of ATP. Cytochrome c contains a heme group, which binds to and transports electrons. The cytochrome c group refers to a class of related cytochromes that have similar structures and functions. These proteins are found in the mitochondria of eukaryotic cells (such as those of plants and animals) and in the inner membranes of bacteria. They play a crucial role in the production of energy within the cell, and are also involved in certain types of programmed cell death (apoptosis).

Cytochromes are a type of hemeprotein found in the mitochondria and other cellular membranes of organisms. They contain a heme group, which is a prosthetic group composed of an iron atom surrounded by a porphyrin ring. This structure allows cytochromes to participate in redox reactions, acting as electron carriers in various biological processes.

There are several types of cytochromes, classified based on the type of heme they contain and their absorption spectra. Some of the most well-known cytochromes include:

* Cytochrome c: a small, mobile protein found in the inner mitochondrial membrane that plays a crucial role in the electron transport chain during cellular respiration.
* Cytochrome P450: a large family of enzymes involved in the metabolism of drugs, toxins, and other xenobiotics. They are found in various tissues, including the liver, lungs, and skin.
* Cytochrome b: a component of several electron transport chains, including those found in mitochondria, bacteria, and chloroplasts.

Cytochromes play essential roles in energy production, detoxification, and other metabolic processes, making them vital for the survival and function of living organisms.

Cytochrome b is a type of cytochrome, which is a class of proteins that contain heme as a cofactor and are involved in electron transfer. Cytochromes are classified based on the type of heme they contain and their absorption spectra.

The cytochrome b group includes several subfamilies of cytochromes, including cytochrome b5, cytochrome b2, and cytochrome bc1 (also known as complex III). These cytochromes are involved in various biological processes, such as fatty acid desaturation, steroid metabolism, and the electron transport chain.

The electron transport chain is a series of protein complexes in the inner mitochondrial membrane that generates most of the ATP (adenosine triphosphate) required for cellular energy production. Cytochrome bc1 is a key component of the electron transport chain, where it functions as a dimer and catalyzes the transfer of electrons from ubiquinol to cytochrome c while simultaneously pumping protons across the membrane. This creates an electrochemical gradient that drives ATP synthesis.

Deficiencies or mutations in cytochrome b genes can lead to various diseases, such as mitochondrial disorders and cancer.

Cytochromes c are a group of small heme proteins found in the mitochondria of cells, involved in the electron transport chain and play a crucial role in cellular respiration. They accept and donate electrons during the process of oxidative phosphorylation, which generates ATP, the main energy currency of the cell. Cytochromes c contain a heme group, an organic compound that includes iron, which facilitates the transfer of electrons. The "c" in cytochromes c refers to the type of heme group they contain (cyt c has heme c). They are highly conserved across species and have been widely used as a molecular marker for evolutionary studies.

Cytochrome b5 is a type of hemoprotein, which is a protein that contains a heme group. The heme group is a cofactor that contains an iron atom and is responsible for the red color of cytochromes. Cytochrome b5 is found in the endoplasmic reticulum and mitochondria of cells and plays a role in various cellular processes, including electron transport and fatty acid desaturation. It can exist in two forms: a soluble form located in the cytosol, and a membrane-bound form associated with the endoplasmic reticulum or mitochondrial inner membrane. The reduced form of cytochrome b5 donates an electron to various enzymes involved in oxidation-reduction reactions.

Nitrate reductases are a group of enzymes that catalyze the reduction of nitrate (NO3-) to nitrite (NO2-). This process is an essential part of the nitrogen cycle, where nitrate serves as a terminal electron acceptor in anaerobic respiration for many bacteria and archaea. In plants, this enzyme plays a crucial role in nitrogen assimilation by reducing nitrate to ammonium (NH4+), which can then be incorporated into organic compounds. Nitrate reductases require various cofactors, such as molybdenum, heme, and/or FAD, for their activity. There are three main types of nitrate reductases: membrane-bound (which use menaquinol as an electron donor), cytoplasmic (which use NADH or NADPH as an electron donor), and assimilatory (which also use NADH or NADPH as an electron donor).

NADPH-ferrihemoprotein reductase, also known as diaphorase or NO synthase reductase, is an enzyme that catalyzes the reduction of ferrihemoproteins using NADPH as a reducing cofactor. This reaction plays a crucial role in various biological processes such as the detoxification of certain compounds and the regulation of cellular signaling pathways.

The systematic name for this enzyme is NADPH:ferrihemoprotein oxidoreductase, and it belongs to the family of oxidoreductases that use NADH or NADPH as electron donors. The reaction catalyzed by this enzyme can be represented as follows:

NADPH + H+ + ferrihemoprotein ↔ NADP+ + ferrohemoprotein

In this reaction, the ferric (FeIII) form of hemoproteins is reduced to its ferrous (FeII) form by accepting electrons from NADPH. This enzyme is widely distributed in various tissues and organisms, including bacteria, fungi, plants, and animals. It has been identified as a component of several multi-enzyme complexes involved in different metabolic pathways, such as nitric oxide synthase (NOS) and cytochrome P450 reductase.

In summary, NADPH-ferrihemoprotein reductase is an essential enzyme that catalyzes the reduction of ferrihemoproteins using NADPH as a reducing agent, playing a critical role in various biological processes and metabolic pathways.

Hydroxymethylglutaryl CoA (HMG-CoA) reductase is an enzyme that plays a crucial role in the synthesis of cholesterol in the body. It is found in the endoplasmic reticulum of cells and catalyzes the conversion of HMG-CoA to mevalonic acid, which is a key rate-limiting step in the cholesterol biosynthetic pathway.

The reaction catalyzed by HMG-CoA reductase is as follows:

HMG-CoA + 2 NADPH + 2 H+ → mevalonic acid + CoA + 2 NADP+

This enzyme is the target of statin drugs, which are commonly prescribed to lower cholesterol levels in the treatment of cardiovascular diseases. Statins work by inhibiting HMG-CoA reductase, thereby reducing the production of cholesterol in the body.

Electron Transport Complex IV is also known as Cytochrome c oxidase. It is the last complex in the electron transport chain, located in the inner mitochondrial membrane of eukaryotic cells and the plasma membrane of prokaryotic cells. This complex contains 13 subunits, two heme groups (a and a3), and three copper centers (A, B, and C).

In the electron transport chain, Complex IV receives electrons from cytochrome c and transfers them to molecular oxygen, reducing it to water. This process is accompanied by the pumping of protons across the membrane, contributing to the generation of a proton gradient that drives ATP synthesis via ATP synthase (Complex V). The overall reaction catalyzed by Complex IV can be summarized as follows:

4e- + 4H+ + O2 → 2H2O

Defects in Cytochrome c oxidase can lead to various diseases, including mitochondrial encephalomyopathies and neurodegenerative disorders.

Cytochrome c1 is a protein that is a part of the electron transport chain in the inner mitochondrial membrane. It is a component of Complex III, also known as the cytochrome bc1 complex. Cytochrome c1 contains a heme group and plays a role in the transfer of electrons from ubiquinol to cytochrome c during oxidative phosphorylation, which is the process by which cells generate energy in the form of ATP. Defects in cytochrome c1 can lead to mitochondrial disorders and have been implicated in the development of certain diseases, such as neurodegenerative disorders and cancer.

Oxidoreductases are a class of enzymes that catalyze oxidation-reduction reactions, which involve the transfer of electrons from one molecule (the reductant) to another (the oxidant). These enzymes play a crucial role in various biological processes, including energy production, metabolism, and detoxification.

The oxidoreductase-catalyzed reaction typically involves the donation of electrons from a reducing agent (donor) to an oxidizing agent (acceptor), often through the transfer of hydrogen atoms or hydride ions. The enzyme itself does not undergo any permanent chemical change during this process, but rather acts as a catalyst to lower the activation energy required for the reaction to occur.

Oxidoreductases are classified and named based on the type of electron donor or acceptor involved in the reaction. For example, oxidoreductases that act on the CH-OH group of donors are called dehydrogenases, while those that act on the aldehyde or ketone groups are called oxidases. Other examples include reductases, peroxidases, and catalases.

Understanding the function and regulation of oxidoreductases is important for understanding various physiological processes and developing therapeutic strategies for diseases associated with impaired redox homeostasis, such as cancer, neurodegenerative disorders, and cardiovascular disease.

Ribonucleotide Reductases (RNRs) are enzymes that play a crucial role in DNA synthesis and repair. They catalyze the conversion of ribonucleotides to deoxyribonucleotides, which are the building blocks of DNA. This process involves the reduction of the 2'-hydroxyl group of the ribose sugar to a hydrogen, resulting in the formation of deoxyribose.

RNRs are highly regulated and exist in various forms across different species. They are divided into three classes (I, II, and III) based on their structure, mechanism, and cofactor requirements. Class I RNRs are further divided into two subclasses (Ia and Ib), which differ in their active site architecture and regulation.

Class Ia RNRs, found in eukaryotes and some bacteria, contain a stable tyrosyl radical that acts as the catalytic center for hydrogen abstraction. Class Ib RNRs, found in many bacteria, use a pair of iron centers to perform the same function. Class II RNRs are present in some bacteria and archaea and utilize adenosine triphosphate (ATP) as a cofactor for reduction. Class III RNRs, found in anaerobic bacteria and archaea, use a unique mechanism involving a radical S-adenosylmethionine (SAM) cofactor to facilitate the reduction reaction.

RNRs are essential for DNA replication and repair, and their dysregulation has been linked to various diseases, including cancer and neurodegenerative disorders. Therefore, understanding the structure, function, and regulation of RNRs is of great interest in biochemistry, molecular biology, and medicine.

... (EC 1.7.2.5) is an enzyme with systematic name nitrous oxide:ferricytochrome-c ... Nitric+oxide+reductase+(cytochrome+c) at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology ... Heiss B, Frunzke K, Zumft WG (June 1989). "Formation of the N-N bond from nitric oxide by a membrane-bound cytochrome bc ... Cheesman MR, Zumft WG, Thomson AJ (March 1998). "The MCD and EPR of the heme centers of nitric oxide reductase from Pseudomonas ...
... nitrate reductases, cytochrome b5 reductases, cytochrome P450 reductases, sulphite reductases, nitric oxide synthases, ... Iwanaga S, Miyata T, Yubisui T, Tamura M, Takeshita M (1986). "Complete amino acid sequence of NADH-cytochrome b5 reductase ... Flavoprotein pyridine nucleotide cytochrome reductases catalyse the interchange of reducing equivalents between one-electron ... A family of flavoprotein pyridine nucleotide cytochrome reductases". J. Biol. Chem. 266 (35): 23542-23547. PMID 1748631. ...
... (EC 1.8.2.4) is an enzyme with systematic name dimethyl sulfide:cytochrome-c2 ... Matched templates Model report Other data Dimethyl+sulfide:cytochrome+c2+reductase at the U.S. National Library of Medicine ... The subunits share homology with other DMSO reductase family enzymes; one example with all three subunits mapped is ... its place in the dimethyl sulphoxide reductase family of microbial molybdopterin-containing enzymes". Molecular Microbiology. ...
Cytochrome+P450+Reductase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) GeneReviews/NCBI/NIH/UW ... Cytochrome P450 reductase (also known as NADPH:ferrihemoprotein oxidoreductase, NADPH:hemoprotein oxidoreductase, NADPH:P450 ... Nicolo C, Flück CE, Mullis PE, Pandey AV (June 2010). "Restoration of mutant cytochrome P450 reductase activity by external ... Lesuisse E, Casteras-Simon M, Labbe P (November 1997). "Cytochrome P-450 reductase is responsible for the ferrireductase ...
... (EC 1.9.6.1, respiratory nitrate reductase, benzyl viologen-nitrate reductase) is an enzyme with ... "Nitrate reductase from Achromobacter fischeri; purification and properties: function of flavines and cytochrome". Archives of ... Nitrate+reductase+(cytochrome) at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology (EC 1.9 ...
The following four human genes encode cytochrome-b5 reductases:[citation needed] CYB5R1 CYB5R2 CYB5R3 CYB5R4 CYB5RL Cytochrome ... Cytochrome-b5 reductase is a NADH-dependent enzyme that converts ferricytochrome from a Fe3+ form to a Fe2+ form. It contains ... Cytochrome-B(5)+Reductase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology (Articles ... and liver NADH-cytochrome b5 reductase by HPLC mapping". Journal of Biochemistry. 101 (5): 1147-59. doi:10.1093/oxfordjournals. ...
... may refer to: Coenzyme Q - cytochrome c reductase, an enzyme NADH dehydrogenase, an enzyme This set ...
In enzymology, an iron-cytochrome-c reductase (created 1972 as EC 1.9.99.1, transferred 2014 to EC 1.9.98.1) is an enzyme that ... This enzyme is also called iron-cytochrome c reductase. This enzyme is part of the electron transport system of Ferrobacillus ... Purification and properties of a heat-labile iron-cytochrome c reductase". J. Biol. Chem. 241 (21): 4872-80. PMID 4288725. ...
... (EC 1.20.2.1, arsenite oxidase) is an enzyme with systematic name arsenite:cytochrome c ... 2 reduced cytochrome c + 2 H+ Arsenate reductase is a molybdoprotein isolated from alpha-proteobacteria that contains iron- ... Arsenate+reductase+(cytochrome+c) at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology ( ... Branco R, Francisco R, Chung AP, Morais PV (August 2009). "Identification of an aox system that requires cytochrome c in the ...
... is a homodimer which contains five c-type heme cofactors per monomer. Four of the heme centers ... Cytochrome c nitrite reductase (ccNiR) (EC 1.7.2.2) is a bacterial enzyme that catalyzes the six electron reduction of nitrite ... "Escherichia coli cytochrome c nitrite reductase NrfA". Meth. Enzymol. Methods in Enzymology. 437: 63-77. doi:10.1016/S0076-6879 ... "Structure of cytochrome c nitrite reductase". Nature. 400 (6743): 476-80. Bibcode:1999Natur.400..476E. doi:10.1038/22802. PMID ...
Other names in common use include cytochrome c2 reductase (reduced nicotinamide adenine dinucleotide, phosphate), cytochrome c2 ... In enzymology, a NADPH-cytochrome-c2 reductase (EC 1.6.2.5) is an enzyme that catalyzes the chemical reaction NADPH + 2 ... and some properties of reduced nicotinamide adenine dinucleotide phosphate-cytochrome C2 reductase from Rhodopseudomonas ... reductase (reduced nicotinamide adenine dinucleotide, and phosphate, NADPH). It employs one cofactor, FAD. Sabo DJ, Orlando JA ...
Cytochrome c1 transfers its electron to cytochrome c (not to be confused with cytochrome c1), and the BH Heme transfers its ... It has four cofactors: cytochrome c1, cytochrome b-562, cytochrome b-566, and a 2-Iron ferredoxin of the Rieske type. The ... cytochrome C1, Rieske protein), 2 core proteins and 6 low-molecular weight proteins. Ubiquinol-cytochrome-c reductase catalyzes ... mtDNA encoded cytochrome b; mutations associated with exercise intolerance CYC1: cytochrome c1 CYCS: cytochrome c UQCRFS1: ...
In enzymology, a trimethylamine-N-oxide reductase (cytochrome c) (EC 1.7.2.3) is an enzyme that catalyzes the chemical reaction ... "Electron transfer and binding of the c-type cytochrome TorC to the trimethylamine N-oxide reductase in Escherichia coli". J. ... Other names in common use include TMAO reductase, and TOR. This enzyme participates in two-component system - general. Arata H ... The systematic name of this enzyme class is trimethylamine:cytochrome c oxidoreductase. ...
Hanukoglu I, Hanukoglu Z (May 1986). "Stoichiometry of mitochondrial cytochromes P-450, adrenodoxin and adrenodoxin reductase ... Adrenodoxin-NADP+ reductase (EC 1.18.1.6, adrenodoxin reductase, nicotinamide adenine dinucleotide phosphate-adrenodoxin ... Adrenodoxin-NADP++reductase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology (EC 1.18.1 ... of a nonheme iron protein and a flavoprotein functional as a reduced triphosphopyridine nucleotide-cytochrome P-450 reductase ...
Hanukoglu I, Hanukoglu Z (May 1986). "Stoichiometry of mitochondrial cytochromes P-450, adrenodoxin and adrenodoxin reductase ... Adrenodoxin reductase (Enzyme Nomenclature name: adrenodoxin-NADP+ reductase, EC 1.18.1.6), was first isolated from bovine ... Hanukoglu I (1996). "Electron transfer proteins of cytochrome P450 systems". Physiological Functions of Cytochrome P450 in ... ferredoxin-NADP+ reductase). Implications for mitochondrial cytochrome P-450 systems". European Journal of Biochemistry. 169 (3 ...
... cytochrome cd1, hydroxylamine (acceptor) reductase, methyl viologen-nitrite reductase, nitrite reductase (cytochrome, and NO- ... Other names in common use include cd-cytochrome nitrite reductase, [nitrite reductase (cytochrome)] [misleading, see comments ... cytochrome c550 and cytochrome cd1 nitrite reductase". Nat. Struct. Biol. 2 (11): 975-982. doi:10.1038/nsb1195-975. PMID ... cytochrome cd1) and copper-containing nitrous oxide reductase from Thiobacillus denitrificans". Arch. Microbiol. 165 (1): 55-61 ...
... and cytochrome cd1 (NirS; SCOP b.70.2), a nitrite reductase. Cytochrome bd is found in plenty of aerobic bacteria, especially ... Cytochrome d, previously known as cytochrome a2, is a name for all cytochromes (electron-transporting heme proteins) that ... but unlike cytochromes a and b, cytochrome D has a heme D instead of a heme A or heme B group. Cytochrome d is part of the ... Cytochrome bd (OPM family 805) is a tri-heme oxidase as it is compound by cytochromes b558, b595 and d. Its main function is ...
Nitric oxide reductase (cytochrome c)), NADPH (EC:1.7.1.14), or Menaquinone (EC:1.7.5.2). Nitric oxide reductase was assigned ... Nitric oxide reductase is in Class 1, therefore it is an oxidoreductases. Nitric oxide reductase belongs to the family of ... Shiro Y (October 2012). "Structure and function of bacterial nitric oxide reductases: nitric oxide reductase, anaerobic enzymes ... Nitric oxide reductase, an enzyme, catalyzes the reduction of nitric oxide (NO) to nitrous oxide (N2O). The enzyme participates ...
Other names include cytochrome P450 reductase, ferrihemoprotein P-450 reductase, and NADPH-dependent cytochrome c reductase. As ... Haas E, Horecker BL, Hogness TR (1940). "The enzymatic reduction of cytochrome c, cytochrome c reductase". J. Biol. Chem. 136: ... WILLIAMS CH Jr; KAMIN H (1962). "Microsomal triphosphopyridine nucleotide-cytochrome c reductase of liver". J. Biol. Chem. 237 ... doi:10.1016/S0021-9258(18)73034-2. Horecker BL (1950). "Triphosphopyridine nucleotide-cytochrome c reductase in liver". J. Biol ...
... mammalian NADH-cytochrome b5 reductase, eukaryotic NADPH-cytochrome P450 reductase, nitrate reductase from plants, nitric-oxide ... A family of flavoprotein pyridine nucleotide cytochrome reductases". J. Biol. Chem. 266 (35): 23542-7. doi:10.1016/S0021-9258( ... Chloroplast ferredoxin-NADP+ reductase (EC 1.18.1.2) may play a key role in regulating the relative amounts of cyclic and non- ... Bacterial ferredoxin-NADP+ reductase may be bound to the thylakoid membrane or anchored to the thylakoid-bound phycobilisomes. ...
"Entrez Gene: CYB5R1 cytochrome b5 reductase 1". Zong NC, Li H, Li H, Lam MP, Jimenez RC, Kim CS, Deng N, Kim AK, Choi JH, ... NADH-cytochrome b5 reductase 1 is an enzyme that in humans is encoded by the CYB5R1 gene. The CYB5R1 gene is located on the 1st ... "NADH-cytochrome b5 reductase 1". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).[permanent dead link] Human CYB5R1 ... mutation at Glu44 and Glu56 of cytochrome b5 on the protein's stabilization and interaction between cytochrome c and cytochrome ...
Nygaard AP (1961). "D(−)-Lactate cytochrome c reductase, a flavoprotein from yeast". J. Biol. Chem. 236: 920-925. Tubbs PK; ...
... cytochrome b5 reductase 2". Zhu H, Qiu H, Yoon HW, Huang S, Bunn HF (December 1999). "Identification of a cytochrome b-type NAD ... Cytochrome b5 reductase 2 is an enzyme that in humans is encoded by the CYB5R2 gene. GRCh38: Ensembl release 89: ... 2005). "Identification of cytochrome-b5 reductase as the enzyme responsible for NADH-dependent lucigenin chemiluminescence in ... 1999). "Identification of a cytochrome b-type NAD(P)H oxidoreductase ubiquitously expressed in human cells". Proc. Natl. Acad. ...
Hanukoglu I, Hanukoglu Z (May 1986). "Stoichiometry of mitochondrial cytochromes P-450, adrenodoxin and adrenodoxin reductase ... ferredoxin-NADP+ reductase). Implications for mitochondrial cytochrome P-450 systems". European Journal of Biochemistry. 169 (3 ... His lab was the first to clone the cDNAs and the gene coding for adrenodoxin reductase - the first enzyme in the electron ... of Psychology). His Ph.D. thesis research on the "Mechanism of electron transport to cytochrome P-450 in adrenal cortex ...
In E. coli, TMAO reductase is encoded by the torCAD operon. The torC gene encodes a pentahemic c-type cytochrome (TorC). TorC ... Trimethylamine N-oxide reductase (TOR or TMAO reductase, EC 1.7.2.3) is a microbial enzyme that can reduce trimethylamine N- ... When comparing TMAO reductase of S. massilia to DMSO reductase from R. Sphaeroides and R. capsulatus, the overall structure is ... However, one major difference in TMAO reductase is a missing tyrosine (Tyr114), in DMSO reductase of R. capsulatus. It is ...
Sanders HK, Becker GE, Nason A (1972). "Glycine-cytochrome c reductase from Nitrobacter agilis". J. Biol. Chem. 247 (7): 2015- ... cytochrome c reductase. This enzyme participates in glycine, serine and threonine metabolism. ... In enzymology, a glycine dehydrogenase (cytochrome) (EC 1.4.2.1) is an enzyme that catalyzes the chemical reaction glycine + ... specifically those acting on the CH-NH2 group of donors with a cytochrome as acceptor. The systematic name of this enzyme class ...
The cytochrome b6f complex (plastoquinol-plastocyanin reductase; EC 1.10.99.1) is an enzyme found in the thylakoid membrane in ... Cytochrome b6f contains seven prosthetic groups. Four are found in both cytochrome b6f and bc1: the c-type heme of cytochrome ... These consist of four large subunits: a 32 kDa cytochrome f with a c-type cytochrome, a 25 kDa cytochrome b6 with a low- and ... Cytochrome b6 and subunit IV are homologous to cytochrome b, and the Rieske iron-sulfur proteins of the two complexes are ...
Cytochrome b5 reductase 4 is an enzyme that in humans is encoded by the CYB5R4 gene. NCB5OR is a flavohemoprotein that contains ... "Entrez Gene: CYB5R4 cytochrome b5 reductase 4". Hartley JL, Temple GF, Brasch MA (2001). "DNA cloning using in vitro site- ... Zhu H, Qiu H, Yoon HW, Huang S, Bunn HF (Jan 2000). "Identification of a cytochrome b-type NAD(P)H oxidoreductase ubiquitously ... functional domains found in both cytochrome b5 (CYB5; MIM 250790) and CYB5 reductase (DIA1; MIM 250800).[supplied by OMIM] ...
Also uses a c-type cytochrome or O 2 as acceptors. Anderson GL, Williams J, Hille R (1992). "The purification and ... Arsenate reductase (azurin) (EC 1.20.9.1) is an enzyme that catalyzes the chemical reaction arsenite + H2O + 2 azurinox ⇌ {\ ...
... (EC 1.7.1.14, fungal nitric oxide reductase, cytochrome P450nor, NOR ( ... Zhang L, Kudo T, Takaya N, Shoun H (September 2002). "The B' helix determines cytochrome P450nor specificity for the electron ... "Denitrification by the fungus Fusarium oxysporum and involvement of cytochrome P-450 in the respiratory nitrite reduction". The ... "Spectroscopic and kinetic studies on reaction of cytochrome P450nor with nitric oxide. Implication for its nitric oxide ...
It is not metabolized significantly by the cytochrome P450 system. The three main metabolites of brexanolone are inactive. The ... Its plasma protein binding is more than 99%. Brexanolone is metabolized by keto-reduction mediated via aldo-keto reductases. ... Mahendroo M, Wilson JD, Richardson JA, Auchus RJ (July 2004). "Steroid 5alpha-reductase 1 promotes 5alpha-androstane-3alpha, ... of allopregnanolone in the brain starts with the conversion of progesterone into 5α-dihydroprogesterone by 5α-reductase. After ...
Nitric oxide reductase (cytochrome c) (EC 1.7.2.5) is an enzyme with systematic name nitrous oxide:ferricytochrome-c ... Nitric+oxide+reductase+(cytochrome+c) at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology ... Heiss B, Frunzke K, Zumft WG (June 1989). "Formation of the N-N bond from nitric oxide by a membrane-bound cytochrome bc ... Cheesman MR, Zumft WG, Thomson AJ (March 1998). "The MCD and EPR of the heme centers of nitric oxide reductase from Pseudomonas ...
Cytochrome b5 reductase is an enzyme in the blood. It controls the amount of iron in your red blood cells, and helps the cells ... Cytochrome b5 reductase is an enzyme in the blood. It controls the amount of iron in your red blood cells, and helps the cells ...
UQCC5 ubiquinol-cytochrome c reductase complex assembly factor 5 [Homo sapiens] UQCC5 ubiquinol-cytochrome c reductase complex ... ubiquinol-cytochrome c reductase complex assembly factor 5provided by HGNC. Primary source. HGNC:HGNC:37257 See related. ... ubiquinol-cytochrome-c reductase complex assembly factor 5. Names. UPF0640 protein C3orf78. small integral membrane protein 4. ... UQCC5 ubiquinol-cytochrome c reductase complex assembly factor 5 [ Homo sapiens (human) ] Gene ID: 440957, updated on 7-Sep- ...
... a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) ... Ubiquinol-cytochrome c reductase): *Superfamily f.32.1: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c ... f.32.1.1: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) [81647] (1 protein). a part (domain) of ... More info for Superfamily f.32.1: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase). Timeline for ...
The patient and several members of her family showed decreased activities of erythrocyte NADH-cytochrome b5 reductase, ... Phenazopyridine induced methaemoglobinaemia associated with decreased activity of erythrocyte cytochrome b5 reductase. ... Phenazopyridine induced methaemoglobinaemia associated with decreased activity of erythrocyte cytochrome b5 reductase. ...
Spectroscopic and kinetic studies of Nor1, a cytochrome P450 nitric oxide reductase from the fungal pathogen Histoplasma ... H. capsulatum contains a P450 nitric oxide reductase homologue (NOR1) that may be important for detoxifying NO during infection ... Spectral characterization of Nor1p indicated that it was similar to other fungal P450 nitric oxide reductases. Nor1p catalyzed ... these results provide evidence for a protective role of a P450 nitric oxide reductase against macrophage-derived NO. ...
Non-heme 11 kDa protein of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) ... Ubiquinol-cytochrome c reductase): *Superfamily f.28.1: Non-heme 11 kDa protein of cytochrome bc1 complex (Ubiquinol-cytochrome ... Ubiquinol-cytochrome c reductase). *Superfamily f.28.1: Non-heme 11 kDa protein of cytochrome bc1 complex (Ubiquinol-cytochrome ... f.28.1.1: Non-heme 11 kDa protein of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) [81530] (2 proteins). "acidic/ ...
NADPH-cytochrome P450 reductase (CPR) and cytochrome-b5 (b5) together with NADH-b5 reductase (b5R) play important roles in ... Role of NADPH-Cytochrome P450 Reductase and Cytochrome-b5/NADH-b5 Reductase in Variability of CYP3A Activity in Human Liver ... Role of NADPH-Cytochrome P450 Reductase and Cytochrome-b5/NADH-b5 Reductase in Variability of CYP3A Activity in Human Liver ... Role of NADPH-Cytochrome P450 Reductase and Cytochrome-b5/NADH-b5 Reductase in Variability of CYP3A Activity in Human Liver ...
Cytochrome P-450 and NADPH-cytochrome P-450 reductase are degraded in the autolysosomes in rat liver. R Masaki, R Masaki ... R Masaki, A Yamamoto, Y Tashiro; Cytochrome P-450 and NADPH-cytochrome P-450 reductase are degraded in the autolysosomes in rat ... inducible cytochrome P-450 (P-450[PB]) and NADPH-cytochrome P-450 reductase (FP2). Autolysosomes, almost completely free from ... Immunochemical and immunoelectron microscope studies on localization of NADPH-cytochrome c reductase on rat liver microsomes. ...
Electron Transfer from Cytochrome P450 Reductase to Cytochrome P450: Towards a Structural and Dynamic Understanding. Goutam ... construction of the functional fused enzyme between rat cytochrome P450c and NADPH-cytochrome P450 reductase, DNA 6(3) (1987) ... 12] Ritacco I, Saltalamacchia A, Spinello A, Ippoliti E, Magistrato A, All-Atom Simulations Disclose How Cytochrome Reductase ... Kinetic studies on a genetically engineered fused enzyme between rat cytochrome P4501A1 and yeast NADPH-P450 reductase, ...
Ubiquinol-cytochrome C reductase core protein II promotes tumorigenesis by facilitating p53 degradation.. ... Ubiquinol-cytochrome C reductase core protein II promotes tumorigenesis by facilitating p53 degradation. EBioMedicine. 2019 Feb ...
Familial idiopathic methemoglobinemia revisited: original cases reveal 2 novel mutations in NADH-cytochrome b5 reductase.. ...
Dive into the research topics of Observations on the reactivation of isooctane-extracted DPNH-cytochrome c reductase with d-[ ... Observations on the reactivation of isooctane-extracted DPNH-cytochrome c reductase with d-[14C]-α-tocopherol. ...
In vivo, nitrite conversion to nitric oxide requires the nitrite reductase activity of xanthine oxidase and cytochrome P-450, ... In vivo, nitrite conversion to nitric oxide requires the nitrite reductase activity of xanthine oxidase and cytochrome P-450, ... which require the nitrite reductase activity of xanthine oxidase and cytochrome P-450. ... which require the nitrite reductase activity of xanthine oxidase and cytochrome P-450. ...
NADPH-cytochrome P450 reductase (CPR) is essential for the detoxification of endogenous and exogenous substances mediated by ... RNA interference of NADPH-cytochrome P450 reductase increases the susceptibility of Aphis gossypii Glover to sulfoxaflor. ... RNA interference of NADPH-cytochrome P450 reductase increases the susceptibility of Aphis ... cytochrome P450. While several insect CPRs have been found to be associated with insecticide resistance, the CPR of Aphis ...
Cytosolic NADH-cytochrome-b5-oxidoreductase (NCB5OR) is ubiquitously expressed in animal tissues. We have previously reported ... Cytochrome-B(5) Reductase / deficiency* * Cytochrome-B(5) Reductase / genetics * Fasting / physiology ... Cytosolic NADH-cytochrome-b5-oxidoreductase (NCB5OR) is ubiquitously expressed in animal tissues. We have previously reported ...
Candida maltosa NADPH-cytochrome P450 reductase: cloning of a full-length cDNA, heterologous expression in Saccharomyces ... Candida maltosa NADPH-cytochrome P450 reductase: cloning of a full-length cDNA, heterologous expression in Saccharomyces ...
Shoun, H.; Fushinobu, S.; Jiang, L.; Kim, S.W.; Wakagi, T. Fungal denitrification and nitric oxide reductase cytochrome P450nor ... including nitrate reductase, nitrite reductase, nitric oxide reductase, and hydroxylamine oxidoreductase. Another category of ... The findings indicate that the activity of N2O reductase could be inhibited in the moderate salinity environment inhibits, ... Salinity can inhibit the activity of N2O reductase, which leads to the increase in cumulative N2O emission [8,9,10]. Wen found ...
Leigh syndrome and cytochrome C oxidase deficiency. * Nicotinamide adenine dinucleotide (NADH) coenzyme Q reductase deficiency ...
M00150 Fumarate reductase, prokaryotes [PATH:eclc00190]. M00417 Cytochrome o ubiquinol oxidase [PATH:eclc00190]. M00157 F-type ...
... cytochrome b-c1 complex ; cytochrome b-c2 complex ; cytochrome bc1 complex ; dihydrocoenzyme Q-cytochrome c reductase ; f-b6 ... coQH2-cytochrome c oxidoreductase ; coenzyme Q-cytochrome c reductase ; coenzyme QH2-cytochrome c reductase ; complex III ; ... cytochrome c oxidoreductase ; ubiquinol-cytochrome c oxidoreductase ; ubiquinol-cytochrome c reductase ; ubiquinol-cytochrome c ... ubiquinol-cytochrome c1 oxidoreductase ; ubiquinol-cytochrome c2 reductase ; ubiquinol:cytochrome c reductase ; ubiquinol: ...
25] The nitrates may induce cytochrome b5 reductase activity. Sodium lauryl sulfate (SLS), a detergent commonly used in ... Epidemiological evaluation of recurrent stomatitis, nitrates in drinking water, and cytochrome b5 reductase activity. Am J ...
... reductase, a key constituent of PMRS. Curcumin also increased the GSH level in erythrocytes and plasma while simultaneously ... Molecular docking results suggest that curcumin interacts with amino acids at the active site cavity of cytochrome ,svg xmlns: ... β-NADH to NADH-cytochrome reductase require higher concentration of curcumin to downregulate the NADH-cytochrome reductase ... We also report the in silico docking of curcumin with cytochrome reductase comparing MoleDock and H-bond score with natural ...
Homo sapiens cytochrome b5 reductase 4 (CYB5R4), mRNA [NM_016230]. GO:0003032(detection of oxygen),GO:0004128(cytochrome-b5 ... cytochrome b5 reductase 4. Hs.5741. ENST00000369679. ref,NM_016230,ens,ENST00000369679,ens,ENST00000369681,gb,CU692982. chr6: ... reductase activity),GO:0005783(endoplasmic reticulum),GO:0006091(generation of precursor metabolites and energy),GO:0006801( ...
Cytochrome C Oxidase. Definition. Complex IV. Term. Succinate Dehydrogenase. Definition. Complex II or Succinate CoQ Reductase ...
On the other hand, microsomal CYPs (e.g., CYP2R1) require only one additional protein, NADPH-cytochrome P450 reductase. All of ... De-orphanization of cytochrome P450 2R1: a microsomal vitamin D 25-hydroxilase ...
cytochrome P-450. b5. cytochromeb5. P-450 reductase. NADPH:P-450 oxidoreductase. anti-CYP2C9-P. polyspecific CYP2C9 antibodies ... Cytochromeb5 (b5; specific content = 41.5 nmol/mg protein) and NADPH:P-450 oxidoreductase (P-450 reductase; specific activity ... 1993) Cytochrome P450TB (CYP2C): A major monooxygenase catalyzing diclofenac 4′-hydroxylation in human liver. Life Sci 52:29-34 ... 1995) Cytochrome P450 inhibitors. Evaluation of specificities in the in vitro metabolism of therapeutic agents by human liver ...
  • NADPH-cytochrome P450 reductase (CPR) and cytochrome- b 5 ( b 5 ) together with NADH- b 5 reductase ( b 5 R) play important roles in cytochrome P450 3A-mediated drug metabolism via electron transfer. (aspetjournals.org)
  • RNA interference of NADPH-cytochrome P450 reductase increases the susceptibility of Aphis gossypii Glover to sulfoxaflor. (bvsalud.org)
  • NADPH-cytochrome P450 reductase ( CPR ) is essential for the detoxification of endogenous and exogenous substances mediated by cytochrome P450 . (bvsalud.org)
  • Candida maltosa NADPH-cytochrome P450 reductase: cloning of a full-length cDNA, heterologous expression in Saccharomyces cerevisiae and function of the N-terminal region for membrane anchoring and proliferation of the endoplasmic reticulum. (mdc-berlin.de)
  • Disruption of the 'Saccharomyces cerevisiae' Gene for NADPH-Cytochrome P450 Reductase Causes Increased Sensitivity to Ketoconazole. (epa.gov)
  • Differentiation of prohaptens from direct acting contact chemical allergens using a cytochrome p450 reductase deficient mouse model. (cdc.gov)
  • In vivo, nitrite conversion to nitric oxide requires the nitrite reductase activity of xanthine oxidase and cytochrome P-450, thus the involvement of these enzymes was also evaluated. (unical.it)
  • Specific inhibition of xanthine oxidase and cytochrome P-450 revealed, in the two teleosts, that the nitrite-dependent inotropism required the nitrite reductase activity of both enzymes. (unical.it)
  • Results suggested that in the heart of C. hamatus and T. bernacchii, nitrite is an integral physiological source of nitric oxide with important signaling properties, which require the nitrite reductase activity of xanthine oxidase and cytochrome P-450. (unical.it)
  • We also found that xanthine oxidase is more expressed in C. hamatus than in T. bernacchii, while the opposite was observed concerning cytochrome P-450. (unical.it)
  • The high potential chain, consisting of the iron sulfur protein, cyt c1 and cyt c2, transfers the first electron from quinol to an acceptor (cytochrome oxidase). (yeastgenome.org)
  • In this study, we characterized the small subunit of ubiquinol-cytochrome C reductase (Bmuccr) of the silkwormBombyx mori, a model insect of Lepidopteron species. (researchgate.net)
  • The ORF contained 354bp and encoded 117 amino acid residues, which shares 69% overall amino acid sequenceidentities with the subunit VII of ubiquinol-cytochrome C reductase from bovine. (researchgate.net)
  • Definition of the homologous of bovine subunit VII of ubiquinol-cytochrome C reductaseshould facilitate further analysis of structure/function relationships of silkworm cytochrome bcl complex. (researchgate.net)
  • The present study was designed to investigate the effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (atorvastatin, pravastatin, simvastatin) on the pharmacokinetics of losartan and its active metabolite EXP-3174 in rats. (karger.com)
  • Ubiquinol-cytochrome C reductase core protein II promotes tumorigenesis by facilitating p53 degradation. (childrensmercy.org)
  • UniProt: Cytochrome c-type protein NrfB. (unam.mx)
  • Nitric oxide reductase (cytochrome c) (EC 1.7.2.5) is an enzyme with systematic name nitrous oxide:ferricytochrome-c oxidoreductase. (wikipedia.org)
  • H. capsulatum contains a P450 nitric oxide reductase homologue (NOR1) that may be important for detoxifying NO during infection. (nih.gov)
  • Spectral characterization of Nor1p indicated that it was similar to other fungal P450 nitric oxide reductases. (nih.gov)
  • Together, these results provide evidence for a protective role of a P450 nitric oxide reductase against macrophage-derived NO. (nih.gov)
  • These prices, cloned and expressed nitric oxide synthase structurally resembles cytochrome p reductase. (njacs.org)
  • Cytochrome P450s (CYP450s) are part of the superfamily of xenobiotic-metabolising enzymes that have been investigated for their effects on various drugs and toxins. (biologists.com)
  • Tolbutamide is a sulfonylurea-type oral hypoglycemic agent whose action is terminated by hydroxylation of the tolylsulfonyl methyl moiety catalyzed by cytochrome P-450 (CYP) enzymes of the human CYP2C subfamily. (aspetjournals.org)
  • The redox partner of microsomal CYPs (including CYP1A1) is NADPH cytochrome P450 oxidoreductase (CPR). (biologists.com)
  • And the above pathways were enriched primarily in the metabolism of xenobiotics by cytochrome P450, drug metabolism-cytochrome P450, and retinol metabolism. (hindawi.com)
  • x]The membrane bound sulfur reducing complex is also comprised of nine major polypeptides including a hydrogenase, sulfur reductase, an electron-transport chain. (kenyon.edu)
  • Phenazopyridine induced methaemoglobinaemia associated with decreased activity of erythrocyte cytochrome b5 reductase. (bmj.com)
  • The effect of HMG-CoA reductase inhibitors on P-gp and cytochrome (CYP) 3A4 activity were also evaluated. (karger.com)
  • The downregulated DEGs were mainly enriched in digestion, basal part of the cell, and aldo-keto reductase (NADP) activity. (hindawi.com)
  • We have investigated the degradation in rat liver of two typical endoplasmic reticulum (ER) membrane proteins, phenobarbital (PB)-inducible cytochrome P-450 (P-450[PB]) and NADPH-cytochrome P-450 reductase (FP2). (rupress.org)
  • This is achieved by oxidizing ubiquinol (ubihydroquinone) which reacts from the membrane phase, reducing cytochrome c in the intermembrane space, and using the free energy change to transport H+ ions across the membrane from the matrix to the inter membrane space. (yeastgenome.org)
  • Coumarins and related compounds inhibit vitamin K1 -2,3 epoxide reductase, preventing vitamin K from being reduced to its active form. (medscape.com)
  • Tolbutamide, an oral hypoglycemic agent, has been used extensively as a metabolic probe to study human cytochrome P-450 (CYP) 3 function. (aspetjournals.org)
  • Studies on diphosphopyridine nucleotide cytochrom c reductase. (springer.com)
  • Overexpression of NADPH-cytochrome P450 reductase is associated with sulfoxaflor resistance and neonicotinoid cross-resistance in Nilaparvata lugens (Stål). (bvsalud.org)
  • Nicotinamide adenine dinucleotide phosphate ( NADPH )- cytochrome P450 reductase ( CPR ), a crucial electron -transfer partner of P450 systems, is required for various biological reactions catalyzed by P450 monooxygenase . (bvsalud.org)
  • 10. Interflavin one-electron transfer in the inducible nitric oxide synthase reductase domain and NADPH-cytochrome P450 reductase. (nih.gov)
  • 15. Role of Ser457 of NADPH-cytochrome P450 oxidoreductase in catalysis and control of FAD oxidation-reduction potential. (nih.gov)
  • Microsomal electron transport chain: monooxygenase activities and relationships between NADPH-cytochrome c-reductase and cytochrome P450 in mouse liver. (unibo.it)
  • The oxidation of isocitrate through IDH activity was coupled to the cytochrome system by NADPH- and NADH-cytochrome c reductase activities. (unboundmedicine.com)
  • Diphenyleneiodonium was the most potent and inhibited NADPH-cytochrome P450 reductase as well, whereas apocynin and Tiron did not. (uncg.edu)
  • NADPH cytochrome P-450 reductase releases FMN and FAD upon dilution into slightly acidic potassium bromide. (tmc.edu)
  • Microsomal protein level, NADPH cytochrome c reductase activity, and the activities and protein levels of cytochrome P-450 isozymes CYP1A1 and CYP2B1 were monitored to assess the effects of AFC exposure on pulmonary P-450. (cdc.gov)
  • Emodin, doxorubicin and organic extracts of C. obtusifolia inhibited NADH:cytochrome c oxidoreductase activity of bovine heart mitochondrial particles and NADH:CoQ oxidoreductase activity of porcine heart mitochondrial NADH dehydrogenase, whereas juglone was stimulatory. (nih.gov)
  • The expression of glutathione (GSH)-dependent enzymes and cytochrome P450 (P450) proteins in freshly isolated proximal tubular cells from human kidney (hPT), and the effect of primary culture on these enzymes, were determined. (aspetjournals.org)
  • Like UQCRC1 in preventing cytochrome c from release, functions of ETC proteins beyond oxidative phosphorylation might also contribute to the pathogenesis of PD. (frontiersin.org)
  • The second problem is linked to the evolution of important enzymatic systems: cytochromes and ABC proteins. (hindawi.com)
  • Cytochromes and ABC proteins, which evolved over time to detoxify food from vegetable chemical "actives," now seem to limit the action of herbal derivatives. (hindawi.com)
  • A diheme cytochrome that transfers electrons across a single membrane, such as the outer membrane of the enterocyte, or the tonoplast membrane of the plant cell vacuole. (genome.jp)
  • Bifunctional diheme cytochrome c thiosul-fate dehydrogenases/tetrathionate reductases (TsdA) exhibit different catalytic properties depend-ing on the source organism. (whiterose.ac.uk)
  • Nitric oxide reductase (cytochrome c) (EC 1.7.2.5) is an enzyme with systematic name nitrous oxide:ferricytochrome-c oxidoreductase. (wikipedia.org)
  • Description: A sandwich ELISA kit for detection of Ubiquinol Cytochrome C Reductase Core Protein II from Mouse in samples from blood, serum, plasma, cell culture fluid and other biological fluids. (orbitalbiosciences.com)
  • 14478 3-oxoacyl-[acyl-carrier protein] reductase fabG BBZA01000001 CDS ARMA_0014 complement(14430. (go.jp)
  • A four minute incubation in FAD reconstituted one half to all of the specific activity, per milligram protein, of untreated reductase, depending upon the substrate. (tmc.edu)
  • 1. Functional interactions in cytochrome P450BM3: flavin semiquinone intermediates, role of NADP(H), and mechanism of electron transfer by the flavoprotein domain. (nih.gov)
  • 17. The flavoprotein component of the Escherichia coli sulfite reductase: expression, purification, and spectral and catalytic properties of a monomeric form containing both the flavin adenine dinucleotide and the flavin mononucleotide cofactors. (nih.gov)
  • It had little flavin dependence, was equimolar in FMN and FAD, and had nearly the specific activity (per mole flavin) of untreated reductase. (tmc.edu)
  • Three-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors (statins) are first-line treatments for hypercholesterolemia. (nih.gov)
  • Studies compared the multiple-dose pharmacokinetic interaction profiles of pravastatin, simvastatin, and atorvastatin when coadministered with 4 inhibitors of cytochrome P450-3A4 isoenzymes in healthy subjects. (nih.gov)
  • Pravastatin has a neutral drug interaction profile relative to cytochrome P450-3A4 inhibitors, but these substrates markedly increase systemic exposure to simvastatin and atorvastatin. (nih.gov)
  • The molecular structure was compared with those of rat NADH-cytochrome b(5) reductase and corn nitrate reductase. (nih.gov)
  • A model of the complex between cytochrome b(5) and the human reductase has been built and compared with that of the haem-containing domain of the nitrate reductase molecule. (nih.gov)
  • The interaction between cytochrome b(5) and the human reductase differs from that of the nitrate reductase because of differences in the amino-acid sequences. (nih.gov)
  • NQO1 is a member of the NAD(P)H dehydrogenase (quinone) family and a cytoplasmic 2-electron reductase. (thermofisher.com)
  • The known components of the ETC are a cytochrome c, two additional cytochromes, but no quinone. (kenyon.edu)
  • 12. Electron transfer in human methionine synthase reductase studied by stopped-flow spectrophotometry. (nih.gov)
  • In the human food-borne intestinal pathogen Campylobacter jejuni , TsdA functions as a tetrathionate reductase en-abling respiration with tetrathionate as an al-ternative electron acceptor. (whiterose.ac.uk)
  • x]The membrane bound sulfur reducing complex is also comprised of nine major polypeptides including a hydrogenase, sulfur reductase, an electron-transport chain. (kenyon.edu)
  • Erythrocyte NADH-cytochrome b(5) reductase reduces methaemoglobin to functional haemoglobin. (nih.gov)
  • 2. Functional interactions in cytochrome P450BM3. (nih.gov)
  • 18. Design of a cytochrome P450BM3 reaction system linked by two-step cofactor regeneration catalyzed by a soluble transhydrogenase and glycerol dehydrogenase. (nih.gov)
  • Neese, F. New Insights into the Nature of Observable Reaction Intermediates in Cytochrome P450 NO Reductase by Using a Combination of Spectroscopy and Quantum Mechanics/Molecular Mechanics Calculations. (mpg.de)
  • Neese, F. The Reaction Mechanism of Cytochrome P450 NO Reductase: A Detailed Quantum Mechanics/Molecular Mechanics Study. (mpg.de)
  • Bennati, M. ENDOR Spectroscopy and DFT Calculations: Evidence for the Hydrogen-Bond Network Within α2 in the PCET of E. coli Ribonucleotide Reductase. (mpg.de)
  • 9. Kinetic, spectroscopic and thermodynamic characterization of the Mycobacterium tuberculosis adrenodoxin reductase homologue FprA. (nih.gov)
  • 7. Affinity isolation and characterization of cytochrome P450 102 (BM-3) from barbiturate-induced Bacillus megaterium. (nih.gov)
  • 8. Expression, purification, and characterization of Bacillus subtilis cytochromes P450 CYP102A2 and CYP102A3: flavocytochrome homologues of P450 BM3 from Bacillus megaterium. (nih.gov)
  • Five mutations in the FAD-binding domain seem to be related to cytochrome b(5). (nih.gov)
  • 5. On the domain structure of cytochrome P450 102 (BM-3): isolation and properties of a 45-kDa FAD/NADP domain. (nih.gov)
  • Freshly isolated hPT cells had relatively high activities of γ-glutamyltransferase, γ-glutamylcysteine synthetase, glutathione S -transferase (GST), glutathione disulfide reductase, and GSH peroxidase. (aspetjournals.org)
  • Alteration of pulmonary cytochrome P-450 system: effects of asphalt fume condensate exposure. (cdc.gov)
  • The human reductase resembles the rat reductase in overall structure as well as in many side chains. (nih.gov)
  • Nevertheless, there is a large main-chain shift from the human reductase to the rat reductase or the corn reductase caused by a single-residue replacement from proline to threonine. (nih.gov)
  • The structures around 15 mutation sites of the human reductase have been examined for the influence of residue substitutions using the program ROTAMER. (nih.gov)
  • The overall molecular structures of the monoclinic and tetragonal forms of cytochrome b 1 are essentially identical. (iucr.org)
  • The statin (HMG-CoA reductase inhibitor) class of drugs has revolutionized the treatment of hypercholesterolemia. (medscape.com)
  • The comprehension of these 2 events may explain the origin of the widespread scepticism of physicians about herbal medicine and suggests that, after correct herbal standardization, use of antagonists of cytochromes and ABC systems will make it possible to recover their pharmacological potential. (hindawi.com)