A group of enzymes that oxidize diverse nitrogenous substances to yield nitrite. (Enzyme Nomenclature, 1992) EC 1.
Salts of nitrous acid or compounds containing the group NO2-. The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. The organic nitrites may be isomeric, but not identical with the corresponding nitro compounds. (Grant & Hackh's Chemical Dictionary, 5th ed)
An enzyme found primarily in BACTERIA and FUNGI that catalyzes the oxidation of ammonium hydroxide to nitrite. It is an iron-sulfur HEME; FLAVOPROTEIN containing siroheme and can utilize both NAD and NADP as cofactors. This enzyme was formerly classified as EC 1.6.6.4.
Oxidoreductases that are specific for the reduction of NITRATES.
Nitrous acid sodium salt. Used in many industrial processes, in meat curing, coloring, and preserving, and as a reagent in ANALYTICAL CHEMISTRY TECHNIQUES. It is used therapeutically as an antidote in cyanide poisoning. The compound is toxic and mutagenic and will react in vivo with secondary or tertiary amines thereby producing highly carcinogenic nitrosamines.
An IRON-containing protein that uses siroheme and 4Fe-4S iron-sulfur centers as prosthetic groups. It catalyzes the six-electron oxidation of AMMONIA to nitrite.
Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.
A subclass of heme a containing cytochromes have a reduced alpha-band absorption of 587-592 nm. They are primarily found in microorganisms.
An enzyme that catalyzes the oxidation of nitrite to nitrate. It is a cytochrome protein that contains IRON and MOLYBDENUM.
A genus of gram-negative, aerobic, motile bacteria that occur in water and soil. Some are common inhabitants of the intestinal tract of vertebrates. These bacteria occasionally cause opportunistic infections in humans.
The type species of gram negative bacteria in the genus ALCALIGENES, found in soil. It is non-pathogenic, non-pigmented, and used for the production of amino acids.
A group of oxidoreductases that act on NADH or NADPH. In general, enzymes using NADH or NADPH to reduce a substrate are classified according to the reverse reaction, in which NAD+ or NADP+ is formally regarded as an acceptor. This subclass includes only those enzymes in which some other redox carrier is the acceptor. (Enzyme Nomenclature, 1992, p100) EC 1.6.
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)
A family of gram-negative bacteria found primarily in the intestinal tracts and mucous membranes of warm-blooded animals. Its organisms are sometimes pathogenic.
Nitrate reduction process generally mediated by anaerobic bacteria by which nitrogen available to plants is converted to a gaseous form and lost from the soil or water column. It is a part of the nitrogen cycle.
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)
A bacterial protein from Pseudomonas, Bordetella, or Alcaligenes which operates as an electron transfer unit associated with the cytochrome chain. The protein has a molecular weight of approximately 16,000, contains a single copper atom, is intensively blue, and has a fluorescence emission band centered at 308nm.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
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.
Gram-negative non-motile bacteria found in soil or brines.
Enzymes that catalyze the reversible reduction of alpha-carboxyl group of 3-hydroxy-3-methylglutaryl-coenzyme A to yield MEVALONIC ACID.
The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Dithionite. The dithionous acid ion and its salts.
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.
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
The type species of the genus NITROSOMONAS, a gram-negative chemolithotroph that oxidizes ammonia to nitrite. It is found in soil, sewage, freshwater, and on building walls, and especially in polluted areas where air contains high levels of nitrogen compounds.
A species of gram-negative, coccoid, mostly chemolithoautotrophic bacteria, in the family RHODOBACTERACEAE. Some strains can grow anaerobically.
Organic compounds that contain the (-NH2OH) radical.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
Catalyzes the oxidation of GLUTATHIONE to GLUTATHIONE DISULFIDE in the presence of NADP+. Deficiency in the enzyme is associated with HEMOLYTIC ANEMIA. Formerly listed as EC 1.6.4.2.
An enzyme that utilizes NADH or NADPH to reduce FLAVINS. It is involved in a number of biological processes that require reduced flavin for their functions such as bacterial bioluminescence. Formerly listed as EC 1.6.8.1 and EC 1.5.1.29.
A FLAVOPROTEIN enzyme that catalyzes the oxidation of THIOREDOXINS to thioredoxin disulfide in the presence of NADP+. It was formerly listed as EC 1.6.4.5
Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A flavoprotein that catalyzes the reduction of heme-thiolate-dependent monooxygenases and is part of the microsomal hydroxylating system. EC 1.6.2.4.
Iron-containing proteins that transfer electrons, usually at a low potential, to flavoproteins; the iron is not present as in heme. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
An enzyme that catalyzes the oxidation and reduction of FERREDOXIN or ADRENODOXIN in the presence of NADP. EC 1.18.1.2 was formerly listed as EC 1.6.7.1 and EC 1.6.99.4.
A colorless inorganic compound (HONH2) used in organic synthesis and as a reducing agent, due to its ability to donate nitric oxide.
A genus of gram-negative, anaerobic, rod-shaped bacteria isolated from the bovine RUMEN, the human gingival sulcus, and dental PULPITIS infections.
A vasodilator that is administered by inhalation. It is also used recreationally due to its supposed ability to induce euphoria and act as an aphrodisiac.
A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.
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)
A family in the order Chromatiales, class GAMMAPROTEOBACTERIA. These are haloalkaliphilic, phototrophic bacteria that deposit elemental sulfur outside their cells.
Proteins found in any species of bacterium.
The rate dynamics in chemical or physical systems.
A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.
Life or metabolic reactions occurring in an environment containing oxygen.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The functional hereditary units of BACTERIA.
A genus of rod-shaped, oval, or bean-shaped bacteria found in soil and fresh water. Polar prosthecae are present and cells reproduce by budding at the tips of the prosthecae. Cells of this genus are aerobic and grow best with one-carbon compounds. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
A FERREDOXIN-dependent oxidoreductase that is primarily found in PLANTS where it plays an important role in the assimilation of SULFUR atoms for the production of CYSTEINE and METHIONINE.
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.
A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.
The type species in the genus RALSTONIA. It is often found in the hospital ward as a contaminant of antiseptic and disinfectant solutions.
A species of bacteria isolated from soil.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
An enzyme of the oxidoreductase class that catalyzes the reaction 7,8-dihyrofolate and NADPH to yield 5,6,7,8-tetrahydrofolate and NADPH+, producing reduced folate for amino acid metabolism, purine ring synthesis, and the formation of deoxythymidine monophosphate. Methotrexate and other folic acid antagonists used as chemotherapeutic drugs act by inhibiting this enzyme. (Dorland, 27th ed) EC 1.5.1.3.
A genus of gram-negative, anaerobic, rod-shaped bacteria capable of reducing sulfur compounds to hydrogen sulfide. Organisms are isolated from anaerobic mud of fresh and salt water, animal intestines, manure, and feces.
A genus of gram-negative, ellipsoidal or rod-shaped bacteria whose major source of energy and reducing power is from the oxidation of ammonia to nitrite. Its species occur in soils, oceans, lakes, rivers, and sewage disposal systems.
Oxidoreductases with specificity for oxidation or reduction of SULFUR COMPOUNDS.
An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.
The type species of gram negative, aerobic bacteria in the genus ACHROMOBACTER. Previously in the genus ALCALIGENES, the classification and nomenclature of this species has been frequently emended. The two subspecies, Achromobacter xylosoxidans subsp. denitrificans and Achromobacter xylosoxidans subsp. xylosoxidans are associated with infections.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A flavoprotein amine oxidoreductase that catalyzes the reversible conversion of 5-methyltetrahydrofolate to 5,10-methylenetetrahydrofolate. This enzyme was formerly classified as EC 1.1.1.171.
1,1'-Bis(phenylmethyl)4,4'-bipyridinium dichloride. Oxidation-reduction indicator.
A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
An NAD-dependent enzyme that catalyzes the oxidation of nitrite to nitrate. It is a FLAVOPROTEIN that contains IRON and MOLYBDENUM and is involved in the first step of nitrate assimilation in PLANTS; FUNGI; and BACTERIA. It was formerly classified as EC 1.6.6.1.
Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
Use of a pulse of X-rays or fast electrons to generate free radicals for spectroscopic examination.
Inorganic salts of sulfurous acid.
Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)
Reductases that catalyze the reaction of peptide-L-methionine -S-oxide + thioredoxin to produce peptide-L-methionine + thioredoxin disulfide + H(2)O.
Compounds that inhibit HMG-CoA reductases. They have been shown to directly lower cholesterol synthesis.
An enzyme of the oxidoreductase class that catalyzes the formation of 2'-deoxyribonucleotides from the corresponding ribonucleotides using NADPH as the ultimate electron donor. The deoxyribonucleoside diphosphates are used in DNA synthesis. (From Dorland, 27th ed) EC 1.17.4.1.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
An enzyme that catalyzes the reduction of 6,7-dihydropteridine to 5,6,7,8-tetrahydropteridine in the presence of NADP+. Defects in the enzyme are a cause of PHENYLKETONURIA II. Formerly listed as EC 1.6.99.7.
Type C cytochromes that are small (12-14 kD) single-heme proteins. They function as mobile electron carriers between membrane-bound enzymes in photosynthetic BACTERIA.
Spherical phototrophic bacteria found in mud and stagnant water exposed to light.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
NAD(P)H:(quinone acceptor) oxidoreductases. A family that includes three enzymes which are distinguished by their sensitivity to various inhibitors. EC 1.6.99.2 (NAD(P)H DEHYDROGENASE (QUINONE);) is a flavoprotein which reduces various quinones in the presence of NADH or NADPH and is inhibited by dicoumarol. EC 1.6.99.5 (NADH dehydrogenase (quinone)) requires NADH, is inhibited by AMP and 2,4-dinitrophenol but not by dicoumarol or folic acid derivatives. EC 1.6.99.6 (NADPH dehydrogenase (quinone)) requires NADPH and is inhibited by dicoumarol and folic acid derivatives but not by 2,4-dinitrophenol.
Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.
Inorganic salts of thiosulfuric acid possessing the general formula R2S2O3.
A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).
A triazine herbicide.
A subclass of enzymes which includes all dehydrogenases acting on carbon-carbon bonds. This enzyme group includes all the enzymes that introduce double bonds into substrates by direct dehydrogenation of carbon-carbon single bonds.
Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
A poisonous dipyridilium compound used as contact herbicide. Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds.
A subtype of thioredoxin reductase found primarily in the CYTOSOL.
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. (From Merck Index, 11th ed)
Highly toxic compound which can cause skin irritation and sensitization. It is used in manufacture of azo dyes.
A family of phototrophic purple sulfur bacteria that deposit globules of elemental sulfur inside their cells. They are found in diverse aquatic environments.
An NAD-dependent enzyme that catalyzes the oxidation of acyl-[acyl-carrier protein] to trans-2,3-dehydroacyl-[acyl-carrier protein]. It has a preference for acyl groups with a carbon chain length between 4 to 16.
Inorganic oxides that contain nitrogen.
A group of dipyridinium chloride derivatives that are used as oxidation-reduction indicators. The general formula is 1,1'-di-R-4,4'-bipyridinium chloride, where R = methyl, ethyl, benzyl or, betaine.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Inorganic compounds that contain tungsten as an integral part of the molecule.
Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Denitrifying Pseudomonas aeruginosa: some parameters of growth and active transport. (1/435)

Optimal cell yield of Pseudomonas aeruginosa grown under denitrifying conditions was obtained with 100 mM nitrate as the terminal electron acceptor, irrespective of the medium used. Nitrite as the terminal electron acceptor supported poor denitrifying growth when concentrations of less than 15 mM, but not higher, were used, apparently owing to toxicity exerted by nitrite. Nitrite accumulated in the medium during early exponential phase when nitrate was the terminal electron acceptor and then decreased to extinction before midexponential phase. The maximal rate of glucose and gluconate transport was supported by 1 mM nitrate or nitrite as the terminal electron acceptor under anaerobic conditions. The transport rate was greater with nitrate than with nitrite as the terminal electron acceptor, but the greatest transport rate was observed under aerobic conditions with oxygen as the terminal electron acceptor. When P. aeruginosa was inoculated into a denitrifying environment, nitrate reductase was detected after 3 h of incubation, nitrite reductase was detected after another 4 h of incubation, and maximal nitrate and nitrite reductase activities peaked together during midexponential phase. The latter coincided with maximal glucose transport activity.  (+info)

Molecular characterization of the nitrite-reducing system of Staphylococcus carnosus. (2/435)

Characterization of a nitrite reductase-negative Staphylococcus carnosus Tn917 mutant led to the identification of the nir operon, which encodes NirBD, the dissimilatory NADH-dependent nitrite reductase; SirA, the putative oxidase and chelatase, and SirB, the uroporphyrinogen III methylase, both of which are necessary for biosynthesis of the siroheme prosthetic group; and NirR, which revealed no convincing similarity to proteins with known functions. We suggest that NirR is essential for nir promoter activity. In the absence of NirR, a weak promoter upstream of sirA seems to drive transcription of sirA, nirB, nirD, and sirB in the stationary-growth phase. In primer extension experiments one predominant and several weaker transcription start sites were identified in the nir promoter region. Northern blot analyses indicated that anaerobiosis and nitrite are induction factors of the nir operon: cells grown aerobically with nitrite revealed small amounts of full-length transcript whereas cells grown anaerobically with or without nitrite showed large amounts of full-length transcript. Although a transcript is detectable, no nitrite reduction occurs in cells grown aerobically with nitrite, indicating an additional oxygen-controlled step at the level of translation, enzyme folding, assembly, or insertion of prosthetic groups. The nitrite-reducing activity expressed during anaerobiosis is switched off reversibly when the oxygen tension increases, most likely due to competition for electrons with the aerobic respiratory chain. Another gene, nirC, is located upstream of the nir operon. nirC encodes a putative integral membrane-spanning protein of unknown function. A nirC mutant showed no distinct phenotype.  (+info)

The GATA factor AreA is essential for chromatin remodelling in a eukaryotic bidirectional promoter. (3/435)

The linked niiA and niaD genes of Aspergillus nidulans are transcribed divergently. The expression of these genes is subject to a dual control system. They are induced by nitrate and repressed by ammonium. AreA mediates derepression in the absence of ammonium and NirA supposedly mediates nitrate induction. Out of 10 GATA sites, a central cluster (sites 5-8) is responsible for approximately 80% of the transcriptional activity of the promoter on both genes. We show occupancy in vivo of site 5 by the AreA protein, even under conditions of repression. Sites 5-8 are situated in a pre-set nucleosome-free region. Under conditions of expression, a drastic nucleosomal rearrangement takes place and the positioning of at least five nucleosomes flanking the central region is lost. Remodelling is strictly dependent on the presence of an active areA gene product, and independent from the NirA-specific and essential transcription factor. Thus, nucleosome remodelling is independent from the transcriptional activation of the niiA-niaD promoter. The results presented cast doubts on the role of NirA as the unique transducer of the nitrate induction signal. We demonstrate, for the first time in vivo, that a GATA factor is involved directly in chromatin remodelling.  (+info)

Nitrite reductase from Pseudomonas aeruginosa released by antimicrobial agents and complement induces interleukin-8 production in bronchial epithelial cells. (4/435)

We have recently reported that nitrite reductase, a bifunctional enzyme located in the periplasmic space of Pseudomonas aeruginosa, could induce interleukin-8 (IL-8) generation in a variety of respiratory cells, including bronchial epithelial cells (K. Oishi et al. Infect. Immun. 65:2648-2655, 1997). In this report, we examined the mode of nitrite reductase (PNR) release from a serum-sensitive strain of live P. aeruginosa cells during in vitro treatment with four different antimicrobial agents or human complement. Bacterial killing of P. aeruginosa by antimicrobial agents induced PNR release and mediated IL-8 production in human bronchial epithelial (BET-1A) cells. Among these agents, imipenem demonstrated rapid killing of P. aeruginosa as well as rapid release of PNR and resulted in the highest IL-8 production. Complement-mediated killing of P. aeruginosa was also associated with PNR release and enhanced IL-8 production. The immunoprecipitates of the aliquots of bacterial culture containing imipenem or complement with anti-PNR immunoglobulin G (IgG) induced twofold-higher IL-8 production than did the immunoprecipitates of the aliquots of bacterial culture with a control IgG. These pieces of evidence confirmed that PNR released in the aliquots of bacterial culture was responsible for IL-8 production in the BET-1A cells. Furthermore, the culture supernatants of the BET-1A cells stimulated with aliquots of bacterial culture containing antimicrobial agents or complement similarly mediated neutrophil migration in vitro. These data support the possibility that a potent inducer of IL-8, PNR, could be released from P. aeruginosa after exposure to antimicrobial agents or complement and contributes to neutrophil migration in the airways during bronchopulmonary infections with P. aeruginosa.  (+info)

PCR detection of genes encoding nitrite reductase in denitrifying bacteria. (5/435)

Using consensus regions in gene sequences encoding the two forms of nitrite reductase (Nir), a key enzyme in the denitrification pathway, we designed two sets of PCR primers to amplify cd1- and Cu-nir. The primers were evaluated by screening defined denitrifying strains, denitrifying isolates from wastewater treatment plants, and extracts from activated sludge. Sequence relationships of nir genes were also established. The cd1 primers were designed to amplify a 778 to 799-bp region of cd1-nir in the six published sequences. Likewise, the Cu primers amplified a 473-bp region in seven of the eight published Cu-nir sequences. Together, the two sets of PCR primers amplified nir genes in nine species within four genera, as well as in four of the seven sludge isolates. The primers did not amplify genes of nondenitrifying strains. The Cu primers amplified the expected fragment in all 13 sludge samples, but cd1-nir fragments were only obtained in five samples. PCR products of the expected sizes were verified as nir genes after hybridization to DNA probes, except in one case. The sequenced nir fragments were related to other nir sequences, demonstrating that the primers amplified the correct gene. The selected primer sites for Cu-nir were conserved, while broad-range primers targeting conserved regions of cd1-nir seem to be difficult to find. We also report on the existence of Cu-nir in Paracoccus denitrificans Pd1222.  (+info)

The blue copper-containing nitrite reductase from Alcaligenes xylosoxidans: cloning of the nirA gene and characterization of the recombinant enzyme. (6/435)

The nirA gene encoding the blue dissimilatory nitrite reductase from Alcaligenes xylosoxidans has been cloned and sequenced. To our knowledge, this is the first report of the characterization of a gene encoding a blue copper-containing nitrite reductase. The deduced amino acid sequence exhibits a high degree of similarity to other copper-containing nitrite reductases from various bacterial sources. The full-length protein included a 24-amino-acid leader peptide. The nirA gene was overexpressed in Escherichia coli and was shown to be exported to the periplasm. Purification was achieved in a single step, and analysis of the recombinant Nir enzyme revealed that cleavage of the signal peptide occurred at a position identical to that for the native enzyme isolated from A. xylosoxidans. The recombinant Nir isolated directly was blue and trimeric and, on the basis of electron paramagnetic resonance spectroscopy and metal analysis, possessed only type 1 copper centers. This type 2-depleted enzyme preparation also had a low nitrite reductase enzyme activity. Incubation of the periplasmic fraction with copper sulfate prior to purification resulted in the isolation of an enzyme with a full complement of type 1 and type 2 copper centers and a high specific activity. The kinetic properties of the recombinant enzyme were indistinguishable from those of the native nitrite reductase isolated from A. xylosoxidans. This rapid isolation procedure will greatly facilitate genetic and biochemical characterization of both wild-type and mutant derivatives of this protein.  (+info)

Bacterial nitric oxide synthesis. (7/435)

The structure-function relationships in nitrite reductases, key enzymes in the dissimilatory denitrification pathway which reduce nitrite to nitric oxide (NO), are reviewed in this paper. The mechanisms of NO production are discussed in detail and special attention is paid to new structural information, such as the high resolution structure of the copper- and heme-containing enzymes from different sources. Finally, some implications relevant to regulation of the steady state levels of NO in denitrifiers are presented.  (+info)

Does the reduction of c heme trigger the conformational change of crystalline nitrite reductase? (8/435)

The structures of nitrite reductase from Paracoccus denitrificans GB17 (NiR-Pd) and Pseudomonas aeruginosa (NiR-Pa) have been described for the oxidized and reduced state (Fulop, V., Moir, J. W. B., Ferguson, S. J., and Hajdu, J. (1995) Cell 81, 369-377; Nurizzo, D., Silvestrini, M. C., Mathieu, M., Cutruzzola, F., Bourgeois, D., Fulop, V., Hajdu, J., Brunori, M., Tegoni, M., and Cambillau, C. (1997) Structure 5, 1157-1171; Nurizzo, D., Cutruzzola, F., Arese, M., Bourgeois, D., Brunori, M., Cambillau, C. , and Tegoni, M. (1998) Biochemistry 37, 13987-13996). Major conformational rearrangements are observed in the extreme states although they are more substantial in NiR-Pd. The four structures differ significantly in the c heme domains. Upon reduction, a His17/Met106 heme-ligand switch is observed in NiR-Pd together with concerted movements of the Tyr in the distal site of the d1 heme (Tyr10 in NiR-Pa, Tyr25 in NiR-Pd) and of a loop of the c heme domain (56-62 in NiR-Pa, 99-116 in NiR-Pd). Whether the reduction of the c heme, which undergoes the major rearrangements, is the trigger of these movements is the question addressed by our study. This conformational reorganization is not observed in the partially reduced species, in which the c heme is partially or largely (15-90%) reduced but the d1 heme is still oxidized. These results suggest that the d1 heme reduction is likely to be responsible of the movements. We speculate about the mechanistic explanation as to why the opening of the d1 heme distal pocket only occurs upon electron transfer to the d1 heme itself, to allow binding of the physiological substrate NO2- exclusively to the reduced metal center.  (+info)

Recently, the structure of a Cu-containing nitrite reductase (NiR) from Hyphomicrobium denitrificans (HdNiR) has been reported, establishing the existence of a new family of Cu-NiR where an additional
The cytochrome cd1 nitrite reductases are enzymes that catalyse the reduction of nitrite to nitric oxide (NO) in the bacterial energy conversion denitrification process. These enzymes contain two different redox centres: one covalently bound c-haem, which is reduced by external donors, and one peculiar d1-haem, where catalysis occurs. In the present paper, we summarize the current understanding of the reaction of nitrite reduction in the light of the most recent results on the enzyme from Pseudomonas aeruginosa and discuss the differences between enzymes from different organisms. We have evidence that release of NO from the ferrous d1-haem occurs rapidly enough to be fully compatible with the turnover, in contrast with previous hypotheses, and that the substrate nitrite is able to displace NO from the d1-haem iron. These results shed light on the mechanistic details of the activity of cd1 nitrite reductases and on the biological role of the d1-haem, whose presence in this class of enzymes has to ...
It is generally assumed that tethering enhances rates of electron harvesting and delivery to active sites in multidomain enzymes by proximity and sampling mechanisms. Here, we explore this idea in a tethered 3-domain, trimeric copper-containing nitrite reductase. By reverse engineering, we find that …
The high-yield expression and purification of cytochrome nitrite reductase (ccNiR), and its own characterization by a variety of methods, notably Laue crystallography, is reported. reduced species, the electrons are distributed amongst the numerous hemes, rather than being localized on specific heme centers. The purified ccNiR yielded good quality crystals, with which the 2.59 ? resolution structure was solved at Slc4a1 room heat using the Laue diffraction method. The structure is similar to that of ccNiR, except in the region where in fact the enzyme interacts using its physiological electron donor (CymA regarding ccNiR, NrfB regarding the proteins). nitrite reductase, NrfA, Laue crystallography, UV/Vis spectropotentiometry, Proteins film voltammetry Launch Ammonia-nitrite interconversion, a significant area of the natural nitrogen cycle, is certainly completed by a number of bacterias within their respiratory procedure. In one path the ammonia oxidizing bacterias (AOB) such as for example make ...
The coupled nitrification-denitrification process plays a pivotal role in cycling and removal of nitrogen in aquatic ecosystems. In the present study, the communities of ammonia oxidizers and denitrifiers in the sediments of 2 basins (Guozhenghu Basin and Tuanhu Basin) of a large urban eutrophic lake (Lake Donghu) were determined using the ammonia monooxygenase subunit A (amoA) gene and the nitrite reductase gene. At all sites of this study, the archaeal amoA gene predominated over the bacterial amoA gene, whereas the functional gene for denitrification nirK gene far outnumbered the nirS gene. Spatially, compared with the Tuanhu Basin, the Guozhenghu Basin showed a significantly greater abundance of the archaeal amoA gene but less abundance of the nirK and nirS genes, while there was no significant difference of bacterial amoA gene copy numbers between the 2 basins. Unlike the archaeal amoA gene, the nirK gene showed a significant difference in community structure between the 2 basins. Archaeal ...
To explain anaerobic nitrite/nitrate production at the expense of ammonium mediated by manganese oxide (Mn(IV)) in sediment, nitrate and manganese respirations were investigated in a strain (Shewanella algae C6G3) presenting these features. In contrast to S. oneidensis MR-1, a biotic transitory nitrite accumulation at the expense of ammonium was observed in S. algae during anaerobic growth with Mn(IV) under condition of limiting electron acceptor, concomitantly, with a higher electron donor stoichiometry than expected. This low and reproducible transitory accumulation is the result of production and consumption since the strain is able to dissimilative reduce nitrate into ammonium. Nitrite production in Mn(IV) condition is strengthened by comparative expression of the nitrate/nitrite reductase genes (napA, nrfA, nrfA-2), and rates of the nitrate/nitrite reductase activities under Mn(IV), nitrate or fumarate conditions. Compared with S. oneidensis MR-1, S. algae contains additional genes that encode
The heme-containing periplasmic nitrite reductase (cd1 NIR) is responsible for the production of nitric oxide (NO) in denitrifying bacterial species, among which are several animal and plant pathogens. Heme NIRs are homodimers, each subunit containing one covalently bound c-heme and one d 1-heme. The reduction of nitrite to NO involves binding of nitrite to the reduced protein at the level of d1-heme, followed by dehydration of nitrite to yield NO and release of the latter. The crucial ratelimiting step in the catalytic mechanism is thought to be the release of NO from the d 1-heme, which has been proposed, but never demonstrated experimentally, to occur when the iron is in the ferric form, given that the reduced NO-bound derivative was presumed to be very stable, as in other hemeproteins. We have measured for the first time the kinetics of NO binding and release from fully reduced cd1 NIR, using the enzyme from Pseudomonas aeruginosa and its site-directed mutant H369A. Quite unexpectedly, we ...
PCR detection of genes encoding nitrite reductase in denitrifying bacteria. Metabolic profiles and genetic diversity of denitrifying communities in activated sludge after addition of methanol or ethanol
Anny Slama-Schwok, Ivan Mikula, Pavel Martasek, Suzanne Durocher, Bulent Mutus, et al.. Only eNOS among the NOS isoforms is a nitrite reductase under hypoxia. Biology, Chemistry and Therapeutic Applications of Nitric Oxide, Aug 2008, Bregenz, Austria. pp.54, ⟨10.1016/j.niox.2008.06.146⟩. ⟨hal-00838925⟩ ...
1KBW: Crystal structure of the soluble domain of the major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria: a new class of copper-containing nitrite reductases.
ID NIRB_ECOLI Reviewed; 847 AA. AC P08201; Q2M731; DT 01-AUG-1988, integrated into UniProtKB/Swiss-Prot. DT 01-NOV-1995, sequence version 4. DT 25-OCT-2017, entry version 161. DE RecName: Full=Nitrite reductase (NADH) large subunit; DE EC=1.7.1.15; GN Name=nirB; OrderedLocusNames=b3365, JW3328; OS Escherichia coli (strain K12). OC Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales; OC Enterobacteriaceae; Escherichia. OX NCBI_TaxID=83333; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RC STRAIN=K12; RX PubMed=2543955; DOI=10.1093/nar/17.10.3865; RA Bell A.I., Gaston K.L., Cole J.A., Busby S.J.W.; RT Cloning of binding sequences for the Escherichia coli transcription RT activators, FNR and CRP: location of bases involved in discrimination RT between FNR and CRP.; RL Nucleic Acids Res. 17:3865-3874(1989). RN [2] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RC STRAIN=K12; RX PubMed=2200672; DOI=10.1111/j.1432-1033.1990.tb19125.x; RA Peakman T., Crouzet J., Mayaux J.F., Busby S.J.W., Mohan S., ...
Title: Cytochrome cd(1) structure: Unusual haem environments in a nitrite reductase and analysis of factors contributing to beta-propeller ...
SWISS-MODEL Template Library (SMTL) entry for 1n90.1. FOLLOWING THE C HEME REDUCTION IN NITRITE REDUCTASE FROM PSEUDOMONAS AERUGINOSA
TY - JOUR. T1 - The role of tryptophan in the ferredoxin-dependent nitrite reductase of spinach. AU - Tripathy, Jatindra N.. AU - Hirasawa, Masakazu. AU - Kim, Sung Kun. AU - Setterdahl, Aaron T.. AU - Allen, James P.. AU - Knaff, David B.. PY - 2007/10/1. Y1 - 2007/10/1. N2 - A system has been developed for expressing a His-tagged form of the ferredoxin-dependent nitrite reductase of spinach in Escherichia coli. The catalytic and spectral properties of the His-tagged, recombinant enzyme are similar, but not identical, to those previously observed for nitrite reductase isolated directly from spinach leaf. A detailed comparison of the spectral, catalytic and fluorescence properties of nitrite reductase variants, in which each of the enzymes eight tryptophan residues has been replaced using site-directed mutagenesis by either aromatic or non-aromatic amino acids, has been used to examine possible roles for tryptophan residues in the reduction of nitrite to ammonia catalyzed by the enzyme.. AB - A ...
Antibodies for proteins involved in ferredoxin-nitrite reductase activity pathways, according to their Panther/Gene Ontology Classification
Identification of the iron-sulfur center of spinach ferredoxin-nitrite reductase as a tetranuclear center, and preliminary EPR studies of mechanism.
1ET7: Catalytic roles for two water bridged residues (Asp-98 and His-255) in the active site of copper-containing nitrite reductase.
1l9s: Directing the mode of nitrite binding to a copper-containing nitrite reductase from Alcaligenes faecalis S-6: characterization of an active site isoleucine.
The ability of Neisseria meningitidis to utilize both oxygen and nitrogen oxides as respiratory substrates allows it to thrive in the diverse environment of the human host. Genome analysis highlighted genes encoding a cbb3 cytochrome oxidase, the aniA nitrite reductase gene and the norB nitric oxide reductase gene. In the present study, we used myxothiazol as an inhibitor of the bc1 complex in intact cells and demonstrated that electron flow to nitrite reductase and the cytochrome oxidase, but not NO reductase, passes via the cytochrome bc1 complex. UV-visible spectrophotometry of intact cells demonstrated that oxygen oxidizes c-type and b-type cytochromes. Oxidation of cytochromes by nitrite was only seen in microaerobically precultured whole cells, and the predominant oxidizable cytochromes were b-type. These are likely to be associated with the oxidation of a b-haem-containing nitric oxide reductase. Nitrite inhibits the oxidation of cytochromes by oxygen in a nitrite reductase-independent ...
TY - JOUR. T1 - The role of tryptophan in the ferredoxin-dependent nitrite reductase of spinach. AU - Tripathy, Jatindra. AU - Hirasawa, Masakazu. AU - Kim, Sung-Kun. AU - Setterdahl, Aaron T.. AU - Allen, James P.. AU - Knaff, David. PY - 2007. Y1 - 2007. M3 - Article. SP - 1. EP - 12. JO - Photosynthesis Research. JF - Photosynthesis Research. SN - 0166-8595. ER - ...
Herein, we demonstrate that the BP-lowering effects of nitrite are enhanced in an experimental model of hypertension and that these effects of nitrite, at least in part, are because of the nitrite reductase activity of erythrocytic XOR. We translate these observations to the clinical setting by demonstration in a proof-of-principle study in hypertensive patients, of similar enhanced bioactivity of nitrite, achieved through dietary provision of inorganic nitrate, and involvement of erythrocytic XOR.. Nitrite caused dose-dependent decreases in BP in SHR, with significant decreases becoming first evident at circulating concentrations of nitrite of ≈1×10−6 mol/L. This concentration falls within the range of physiological levels of circulating nitrite, that is, 0.2 to 5.0×10−6 mol/L that have been reported in healthy humans.26,30-32 Crucially at this dose, nitrite had minimal effects on BP in the normotensive WKY control. In our studies, the potassium nitrite salt decreased BP in a ...
Fingerprint Dive into the research topics of Mechanisms of nitrite reduction to nitric oxide in the heart and vessel wall. Together they form a unique fingerprint. ...
(a) Reduction of nitrite to ammonia is carried out by an enzyme called nitrite reductase. (b)This enzyme does not contain molybednum but requires copper and iron as activators. It requires reducing power, which is NADPH. …
TIGR02376 (PSSM ID: 131429): Conserved Protein Domain Family Cu_nitrite_red, This family consists of copper-type nitrite reductase
This study provides a novel analysis of N-regulated gene networks conserved across two highly divergent species: rice (a monocot) and Arabidopsis (a dicot). Despite their large phylogenetic distance, our analysis revealed a set of N-regulated genes, TFs, and network modules conserved in rice and Arabidopsis exposed to the same N-treatment conditions. Our analysis shows a statistically significant overlap, indicating that rice and Arabidopsis respond very similarly to the N treatments. The list of genes regulated by N treatments in rice includes many of the known nitrate/ammonium-regulated genes previously identified in Arabidopsis, including genes known to respond to nitrate (Nitrate Reductase, Nitrite Reductase, Ferredoxin, Ferredoxin-Dependent NADPH Reductase, and G6PDH). These results are not surprising in hindsight, given that the former are important to reduce the plants risk of nitrite toxicity. Selected genes from the N-responsive lists were corroborated by RT-qPCR analysis. One of the ...
Probable electron donor to membrane cytochrome oxidase and to periplasmic nitrite reductase. Membrane-binding site participates in protein-protein interaction ...
This study focuses on the chemical reaction between Fe(II) and nitrite, which has been reported to produce high levels of the greenhouse gas N2O. We investigated the extent to which dead biomass and Fe(II) minerals might enhance this reaction. Here, nitrite reduction was highest when both additives were present but less pronounced if only Fe(II) minerals were added. Both reaction systems show distinct differences, rather low N2O levels, and indicated the abiotic production of N2 ...
TY - JOUR. T1 - Enzymatic properties of the ferredoxin-dependent nitrite reductase from chlamydomonas reinhardtii. Evidence for hydroxylamine as a late intermediate in ammonia production. AU - Hirasawa, Masakazu. AU - Tripathy, Jatindra N.. AU - Sommer, Frederik. AU - Somasundaram, Ramasamy. AU - Chung, Jung Sung. AU - Nestander, Matthew. AU - Kruthiventi, Mahima. AU - Zabet-Moghaddam, Masoud. AU - Johnson, Michael K.. AU - Merchant, Sabeeha S.. AU - Allen, James Paul. AU - Knaff, David B.. PY - 2010/1. Y1 - 2010/1. N2 - The ferredoxin-dependent nitrite reductase from the green alga Chlamydomonas reinhardtii has been cloned, expressed in Escherichia coli as a His-tagged recombinant protein, and purified to homogeneity. The spectra, kinetic properties and substrate-binding parameters of the C. reinhardtii enzyme are quite similar to those of the ferredoxin-dependent spinach chloroplast nitrite reductase. Computer modeling, based on the published structure of spinach nitrite reductase, predicts ...
UNLABELLED Nitrate reduction to nitrite in oil fields appears to be more thermophilic than the subsequent reduction of nitrite. Concentrated microbial consortia from oil fields reduced both nitrate and nitrite at 40 and 45°C but only nitrate at and above 50°C. The abundance of the nirS gene correlated with mesophilic nitrite reduction activity. Thauera and Pseudomonas were the dominant mesophilic nitrate-reducing bacteria (mNRB), whereas Petrobacter and Geobacillus were the dominant thermophilic NRB (tNRB) in these consortia. The mNRB Thauera sp. strain TK001, isolated in this study, reduced nitrate and nitrite at 40 and 45°C but not at 50°C, whereas the tNRB Petrobacter sp. strain TK002 and Geobacillus sp. strain TK003 reduced nitrate to nitrite but did not reduce nitrite further from 50 to 70°C. Testing of 12 deposited pure cultures of tNRB with 4 electron donors indicated reduction of nitrate in 40 of 48 and reduction of nitrite in only 9 of 48 incubations. Nitrate is injected into high
10. Appendix. Do Inquiry Before Purchasing Report Here: http://www.marketsnresearch.com/inquiry-for-buying.html?repid=9510. Secondly, Calcium Nitrite Market report includes, development policies and plans are discussed, manufacturing processes and cost structures. This Calcium Nitrite Industry report also states import/export, supply and consumption figures as well as cost, price, Global Calcium Nitrite Market gross margin and revenue by Key regions (North America, Europe, Japan, China, South East Asia, India) and other regions can be added.. Then, the report pay attention on worldwide Calcium Nitrite that major leading market players in Calcium Nitrite industry area with information such as Company Profile of Calcium Nitrite Market, Sales Volume, Price, Gross Margin of Calcium Nitrite Market and contact information. Global Calcium Nitrite Industry report also includes Calcium Nitrite Upstream raw materials and Calcium Nitrite downstream consumers analysis.. ...
Modified tetrapyrroles such as chlorophyll, heme, siroheme, vitamin B(12), coenzyme F(430), and heme d(1) underpin a wide range of essential biological functions in all domains of life, and it is therefore surprising that the syntheses of many of these life pigments remain poorly understood. It is known that the construction of the central molecular framework of modified tetrapyrroles is mediated via a common, core pathway. Herein a further branch of the modified tetrapyrrole biosynthesis pathway is described in denitrifying and sulfate-reducing bacteria as well as the Archaea. This process entails the hijacking of siroheme, the prosthetic group of sulfite and nitrite reductase, and its processing into heme and d(1) heme. The initial step in these transformations involves the decarboxylation of siroheme to give didecarboxysiroheme. For d(1) heme synthesis this intermediate has to undergo the replacement of two propionate side chains with oxygen functionalities and the introduction of a double bond into
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50 parameters and over 100 measurement ranges agents Reduction Ammonium Cadmium Nitrate Lead Phosphate Copper Nitrite Zinc Surfactants TNb units Bitter in the laboratory via Ethernet 3 The reference sample is analysed at the laboratory using a cuvette test and the photometer ...
TY - CHAP. T1 - Nitrous oxide reductase. AU - DellAcqua, Simone. AU - Pauleta, Sofia R.. AU - Moura, Isabel Maria Andrade Martins Galhardas de. N1 - Sem PDF. PY - 2013. Y1 - 2013. M3 - Chapter. SN - 978-1-4614-1532-9. T3 - Encyclopedia of Metalloproteins. BT - Nitrous oxide reductase. A2 - Kretsinger, R.H.. A2 - Uversky, V. N.. A2 - Permyakov, E.A.. PB - Springer. ER - ...
Nitrites are abused mainly by older adolescents and adults. Typically, individuals who abuse nitrites are seeking to enhance sexual function and pleasure. Research shows that abuse of these drugs in this context is associated with unsafe sexual practices that greatly increase the risk of contracting and spreading infectious diseases such as HIV/AIDS and hepatitis.. Animal research raises the possibility that there may also be a link between abuse of nitrites and the development and progression of infectious diseases and tumors. The research indicates that inhaling nitrites depletes many cells in the immune system and impairs mechanisms that fight infectious diseases. A study found that even a relatively small number of exposures to butyl nitrite can produce dramatic increases in tumor incidence and growth rate in animals.. ...
A new five-year award from the U.S. Department of Educations Office of Special Education and Rehabilitation Services will enable FPG to build on the work of its seminal center on State Implementation and Scaling Up of Evidence Based Practices (SISEP). Over the last decade, the SISEP Center has supported state and local education agencies as they have worked toward building their capacity for obtaining improved outcomes for students with disabilities, their families, and educators.. Were thrilled to continue and to expand upon the past ten years of work of the SISEP Center, said Caryn Ward, the centers current co-principal investigator, who will head the project through its next grant. SISEP has strengthened our education systems by supporting our educators in making a difference for students and families.. Ward said that as a longtime cornerstone in FPGs National Implementation Research Network (NIRN) portfolio, SISEP has informed the sciences of implementation, improvement, and ...
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Handing challenges off to a single individual or inadvertently letting a challenge linger is not likely to be helpful. Most challenges that benefit from rapid-cycle problem-solving require quickly pulling together the right team to engage in the PDSA process. An Implementation Team is accountable for forming this PDSA team and supporting their work. The first step in creating a Rapid Cycle Problem Solving Team is to identify a team lead who will take responsibility for pulling together the team, organizing the process, and seeing it through to a successful conclusion. The team lead needs to gather the right people to solve the particular problem under consideration. These are people who have a stake in the outcome, who have expertise and information relevant to the problem at hand, and who have authority to make necessary changes to solve the problem or access to decision-makers. The problem-solving team might be a selected subset of the Implementation Team and it might involve inviting some ...
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Sodium nitrite is a chemical compound used to keep processed foods fresh and brightly colored. Though studies show that it may...
MetabolismBiosynthesis of cofactors, prosthetic groups, and carriersFolic acidmethylenetetrahydrofolate reductase (TIGR00677; EC 1.5.1.20; HMM-score: 68.3) ...
The denitrifying bacterium Paracoccus denitrificans can grow aerobically or anaerobically using nitrate or nitrite as the sole nitrogen source. The biochemical pathway responsible is expressed from a gene cluster comprising a nitrate/nitrite transporter (NasA), nitrite transporter (NasH), nitrite reductase (NasB), ferredoxin (NasG) and nitrate reductase (NasC). NasB and NasG are essential for growth with nitrate or nitrite as the nitrogen source. NADH serves as the electron donor for nitrate and nitrite reduction, but only NasB has a NADH-oxidizing domain. Nitrate and nitrite reductase activities show the same Km for NADH and can be separated by anion-exchange chromatography, but only fractions containing NasB retain the ability to oxidize NADH. This implies that NasG mediates electron flux from the NADH-oxidizing site in NasB to the sites of nitrate and nitrite reduction in NasC and NasB respectively. Delivery of extracellular nitrate to NasBGC is mediated by NasA, but both NasA and NasH ...
The cytochrome cd₁ nitrite reductase from Paracoccus pantotrophus catalyses the one electron reduction of nitrite to nitric oxide using two heme cofactors. The site of nitrite reduction is the d₁ heme, which is synthesized under anaerobic conditions by using nirECFD-LGHJN gene products. In vivo studies with an unmarked deletion strain, ΔnirF, showed that this gene is essential for cd₁ assembly and consequently for denitrification, which was restored when the ΔnirF strain was complemented with wild-type, plasmid-borne, nirF. Removal of a signal sequence and deletion of a conserved N-terminal Gly-rich motif from the NirF coded on a plasmid resulted in loss of in vivo NirF activity. We demonstrate here that the product of the nirF gene is a periplasmic protein and, hence, must be involved in a late stage of the cofactor biosynthesis. In vitro studies with purified NirF established that it could bind d₁ heme. It is concluded that His41 of NirF, which aligns with His200 of the d₁ heme domain of
Colonization by Alcaligenes xylosoxidans in children with cystic fibrosis: a retrospective clinical study conducted by means of molecular epidemiological investigation
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We examined the effects of nitrite repletion on mitochondrial function, reperfusion ROS generation, organ function, and survival in a 12-minute mouse cardiac arrest model. Cardiac arrest results in systemic nitrite depletion, and low-dose nitrite replacement (therapy with 50 nmol) at CPR initiation restores these levels to near baseline and increases cardiac S-nitrosothiols. Therapeutic nitrite repletion and S-nitrosation in heart are associated with transient, reversible inhibition of complex I, reducing mitochondrial reperfusion, ROS generation, and oxidative injury. Nitrite improved pulmonary gas exchange, cardiac contractility, and survival with a suggestion of neuroprotection.. Moderate NO reperfusion therapy is known to be protective,29 but NO formation is limited by the dependence of NO synthase on oxygen and reduced substrates.30 Nitrite acts as a reservoir for NO during ischemia, and nitrite reduction generates NO through NOS-independent pathways.6,31,32 We demonstrate that global ...
We examined the effects of nitrite repletion on mitochondrial function, reperfusion ROS generation, organ function, and survival in a 12-minute mouse cardiac arrest model. Cardiac arrest results in systemic nitrite depletion, and low-dose nitrite replacement (therapy with 50 nmol) at CPR initiation restores these levels to near baseline and increases cardiac S-nitrosothiols. Therapeutic nitrite repletion and S-nitrosation in heart are associated with transient, reversible inhibition of complex I, reducing mitochondrial reperfusion, ROS generation, and oxidative injury. Nitrite improved pulmonary gas exchange, cardiac contractility, and survival with a suggestion of neuroprotection.. Moderate NO reperfusion therapy is known to be protective,29 but NO formation is limited by the dependence of NO synthase on oxygen and reduced substrates.30 Nitrite acts as a reservoir for NO during ischemia, and nitrite reduction generates NO through NOS-independent pathways.6,31,32 We demonstrate that global ...
Nitrite poisoning is also known by aquarists as Brown Blood Disease. Nitrite damages the nervous system, liver, spleen, and kidneys of fish and other aquatic animals. Even low concentrations of 0.5mg/l over extended periods can cause long term damage. Nitrite binds the oxygen carrying hemoglobin in blood therefore fish can suffocate even if the oxygen in the tank is sufficient. Given time (normally 3-4 weeks) in a normal process of a new tank cycling, nitrites are converted into the much less toxic nitrates by the nitrifying bacteria. However if the levels of nitrites do not come down, then the nitrites will cause the animals to struggle for oxygen as the nitrites damage the gills of fish and will cause long term damage to their immune systems and stress them greatly. ...
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dietary nitrate/nitrite could be a compensatory fuel for a disrupted nitrate/nitrite/NO pathway and related disorders in diabetes
A sequence of equations is proposed for the decomposition events of alkyl nitrates, based on the observation that nitrites are produced in substantial amounts. Studies were made of the reactions of ethoxyl radicals (produced by the decomposition of diethyl peroxide at 181 deg C) with ethyl nitrite and NO. The reaction rate between the ethoxyl radicals and NO was much greater than that between the radicals the nitrite.
Its now day 8 since I started dosing my 15Gl tank with pure ammonia. I managed to get the level of ammonia to about 3ppm and for the last couple of days the numbers have been dropping. Today I read the result as 0.5. Im using the api liquid test kit and have double checked and asked other peoples advice on the readings. The strips that I was using indicated that there was no nitrites present in my tank and I figured the strips were simply wrong, however today I tested for nitrites with an
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Read Nitrite and Nitrate in Human Health and Disease by with Rakuten Kobo. This fully revised and updated new edition provides a comprehensive look at nitrite and nitrate and their effect on huma...
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Once the pair nitrate-nitrite--in quantity respectively set by the ingestion level or transformation level by intestinal bacteria--has entered through the intestinal mucosa, it may react with active biochemical groups. Nitrite, owing to its high oxido-reduction potential, may induce the oxidation of a large number of compounds, as for example the Fe++ heme-Fe+++ hemine system, reduced cytochromes-oxidized cytochromes system, etc. If the presence of nitrite in blood is not clearly established, this is due to the nitrite high chemical reactivity. Moreover, a transformation by the tissues of nitrates into nitrites after a nitro-reduction is quite possible.
Potassium nitrite, Kaliumnitrit, is a salt with chemical formula KNO2, purity minimum 97 %. Available in 25 kg UN drums, from stock in the Netherlands
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Alkyl nitrites, more commonly known as poppers are volatile substances which, when inhaled, can cause a high and/or enhance sexual experience.
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Hi Aquanuts! I have a water issue. Ive been cycling my system for about a month now. Ive had nitrites at 5ppm and nitrates at 5ppm for the last 2 weeks.…
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1 Cytochromes-C-Reduced[c] + 1 NITRITE[c] + 2 PROTON[c] =, 1 Cytochromes-C-Oxidized[c] + 1 NITRIC-OXIDE[c] + 1 WATER[c] ... PWY-6523, nitrite-dependent anaerobic methane oxidation: *1 reactions found over 3 reactions in the full pathway ... Retrieved from "http://gem-aureme.genouest.org//cokagem/index.php?title=NITRITE-REDUCTASE-CYTOCHROME-RXN&oldid=6022" ...
Structure of the bound dioxygen species in the cytochrome oxidase reaction of cytochrome cd1 nitrite reductase. ...
By nitrite reductase on Sun, 01/24/2021 - 12:12pm. Something I found fascinating was that many (most?) Back Bay buildings rest ...
Induced Rescue of Catalytic Activity in Deactivated Nitrite Reductase Mutant. Chemistry - a European journal, 26(66), pp. 15206 ...
Ferredoxin--nitrite reductase 39.62 796 aa 50.8 0.000006 Natranaerobius thermophilus JW/NM-WN-LF Bacteria normal 0.268202 ...
Transporters and assimilatory reductases for nitrate and nitrite, and nitric oxide-detoxifying mechanisms (flavohemoglobin and ... Transporters and assimilatory reductases for nitrate and nitrite, and nitric oxide-detoxifying mechanisms (flavohemoglobin and ... Transporters and assimilatory reductases for nitrate and nitrite, and nitric oxide-detoxifying mechanisms (flavohemoglobin and ... Transporters and assimilatory reductases for nitrate and nitrite, and nitric oxide-detoxifying mechanisms (flavohemoglobin and ...
DISSIMILATORY COPPER-CONTAINING NITRITE REDUCTASE publication title X-Ray Structure of a Blue Copper Nitrite Reductase at High ... X-ray structure of a blue copper nitrite reductase at high ph and in copper free form at 1.9 a resolution ...
Copper-containing nitrite reductase source organism Alcaligenes faecalis ec nomenclature. ec 1.7.2.1: Nitrite reductase (NO- ... Directed evolution of copper nitrite reductase to a chromogenic reductant. pubmed doi rcsb molecule tags Oxidoreductase ...
1 NITRITE[e] + 2 PROTON[e] + 1 Reduced-cytochromes-c551[e] ,=, 1 NITRIC-OXIDE[e] + 1 Oxidized-cytochromes-c551[e] + 1 WATER[e] ... nitrite reductase (no-forming). *direction: *reversible. *ec-number: *ec-1.7.2.1. Reaction formula. * ...
Deoxymyoglobin is a nitrite reductase that generates nitric oxide and regulates mitochondrial respiration. S Shiva, Z Huang, R ... Hypoxia, red blood cells, and nitrite regulate NO-dependent hypoxic vasodilation. JH Crawford, TS Isbell, Z Huang, S Shiva, BK ...
Nitrite reductase genes sequence accessions Nitrite reductase genes sequence accessions Spatiotemporal characterization of nirK ...
This is an extensively derivatised heme; a comparison is drawn with another type of respiratory nitrite reductase in which the ... In contrast to the widespread c-type cytochromes, the d1 heme is restricted to a single enzyme, the cytochrome cd1 nitrite ... reductase that catalyses the one-electron reduction of nitrite to nitric oxide. ... the cytochrome cd1 nitrite reductase that catalyses the one-electron reduction of nitrite to nitric oxide. This is an ...
formate-dependent nitrite reductase complex subunit NrfG. COGs. COG4235. -. Cytochrome c biogenesis factor (O). ...
Dissecting the role of NtrC and RpoN in the expression of assimilatory nitrate and nitrite reductases in Bradyrhizobium ... Development and application of an electronic tongue for detection and monitoring of nitrate, nitrite and ammonium levels in ... nitrite and ammonium in water. The electronic tongue was composed of an ... ...
Dissecting the role of NtrC and RpoN in the expression of assimilatory nitrate and nitrite reductases in Bradyrhizobium ... Development and application of an electronic tongue for detection and monitoring of nitrate, nitrite and ammonium levels in ... nitrite and ammonium in water. The electronic tongue was composed of an ... ...
periplasmic nitrate (or nitrite) reductase c-type cytochrome, NapC/NirT family 49.46 ... periplasmic nitrate (or nitrite) reductase c-type cytochrome, NapC/NirT family 43.32 ... periplasmic nitrate (or nitrite) reductase c-type cytochrome, NapC/NirT family 42.78 ... periplasmic nitrate (or nitrite) reductase c-type cytochrome, NapC/NirT family 42.25 ...
Novel nitrite reductase domain structure suggests a chimeric denitrification repertoi.... Sarah Schwartz, Lily Momper, L. ...
Genes showing the strongest oxygen-dependent adaption encoded nitrate (narGHJI) and nitrite (nirBD) reductases. Together with ...
Metabolism Central intermediary metabolism Nitrogen metabolism nitrite reductase [NAD(P)H], large subunit (TIGR02374; EC 1.7. ... putative selenate reductase, YgfK subunit (TIGR03315; HMM-score: 17.9) Metabolism Energy metabolism Amino acids and amines ... Metabolism Energy metabolism Electron transport thioredoxin-disulfide reductase (TIGR01292; EC 1.8.1.9; HMM-score: 32.3) ... Cellular processes Cellular processes Detoxification mercury(II) reductase (TIGR02053; EC 1.16.1.1; HMM-score: 25.8) ...
Nitrite and sulphite reductase 4Fe-4S domain. A. PF03460 NIR_SIR_ferr. Nitrite/Sulfite reductase ferredoxin-like half domain. ... Sulfite Reductase Hemoprotein;Domain 2. 3aopA02. 4S39A 3MM5B 2AOPA 3B0HA 3B0NA 3GEOA 3VLXA 3VKPA 4S3DA 3MM7A 4G9PA 3VKTA 4HTRA ... Sulfite Reductase Hemoprotein; domain 1. Sulfite Reductase Hemoprotein, domain 1. 3aopA03. 3.90.480.10. Alpha Beta. Alpha-Beta ... Sulfite Reductase Hemoprotein; domain 1. Sulfite Reductase Hemoprotein, domain 1. 3aopA01. 3.30.413.10. Alpha Beta. 2-Layer ...
Adsorbing surface strongly influences the pseudoperoxidase and nitrite reductase activity of electrode-bound yeast cytochrome c ... Catalytic Reduction of Dioxygen and Nitrite Ion at a Met80Ala Cytochrome c-Functionalized Electrode. 2008. Casalini, Stefano; ...
The c-heme rapidly oxidised and nitrite was reduced to NO at the d(1)-heme. A slower equilibration of electrons followed, ... A previous study of nitrite reduction by Paracoccus pantotrophus cytochrome cd(1) at pH 7.0 identified early reaction ... Cytochromes, Hydrogen-Ion Concentration, Kinetics, Nitric Oxide, Nitrite Reductases, Nitrites, Oxidation-Reduction, Paracoccus ... The c-heme rapidly oxidised and nitrite was reduced to NO at the d(1)-heme. A slower equilibration of electrons followed, ...
Metabolism Energy metabolism Electron transport cytochrome c nitrite reductase, Fe-S protein (TIGR03149; EC 1.7.2.2; HMM-score ... Metabolism Energy metabolism Aerobic periplasmic nitrate reductase, large subunit (TIGR01706; EC 1.7.99.4; HMM-score: 289.5) ... Metabolism Energy metabolism Electron transport periplasmic nitrate reductase, large subunit (TIGR01706; EC 1.7.99.4; HMM-score ... anaerobic dimethyl sulfoxide reductase, A subunit, DmsA/YnfE family (TIGR02166; HMM-score: 168.7) ...
Nitrite Reductase Gene Upregulated During Conidiation Is Involved in Macroconidium Formation in Fusarium oxysporum ...
NH3 + NADP+ + H2O <=> nitrite + NADPH + H+ 1.7.1.4 nitrite reductase [NAD(P)H] 1.7.7.1 ferredoxin---nitrite reductase 1.8.1.2 ... 1.7.1.10 hydroxylamine reductase (NADH) 1.7.1.15 nitrite reductase (NADH) 1.7.1.4 nitrite reductase [NAD(P)H] - - - ... 1.7.1.10 hydroxylamine reductase (NADH) 1.7.1.4 nitrite reductase [NAD(P)H] 1.7.99.1 hydroxylamine reductase - - - ... nitrite + H2O + NADP+ <=> H+ + nitrate + NADPH 1.7.1.1 nitrate reductase (NADH) 1.7.1.2 nitrate reductase [NAD(P)H] 1.7.1.3 ...
formate-dependent nitrite reductase, 4Fe4S subunit[1], B4072[2][1], YjcJ[2][1], NrfC[2][1] , ECK4065, JW4033, yjcJ, b4072 ...
... the other enzyme we have looked at is nitrite reductase (NiR), specifically copper-based NiR as it has a much cleaner reaction ... if appropriate as a potential cancer therapeutic we decided to look into genes for nitric oxide synthase and nitrite reductase ...
Within the microcrystal population of copper nitrite reductase, two polymorphs with different unit-cell sizes were successfully ...
... the enzyme that converts nitrates to nitrite, so your urine, even if you have a UTI, maybe negative for nitrites, however, it ... Please be aware that about a third of UTIs are caused by bacteria that dont produce nitrate reductase, ... Please be aware in the context of a UTI the dipsticks assess two main things; (1) urine nitrite levels and (2) the presence of ... However, positive protein and red blood cells in the absence of the white cells and nitrites are not indicative of a UTI and ...
Nitric oxide reductase (norB) gene sequence analysis reveals discrepancies with nitrite reductase (nir) gene phylogeny in ...
  • In enzymology, a ferredoxin-nitrite reductase (EC 1.7.7.1) is an enzyme that catalyzes the chemical reaction NH3 + 2 H2O + 6 oxidized ferredoxin ⇌ {\displaystyle \rightleftharpoons } nitrite + 6 reduced ferredoxin + 7 H+ The 3 substrates of this enzyme are NH3, H2O, and oxidized ferredoxin, whereas its 3 products are nitrite, reduced ferredoxin, and H+. (wikipedia.org)
  • Below are the list of possible Ferredoxin--nitrite reductase products. (mybiosource.com)
  • Ferredoxin-Nitrite Reductase" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (sickkids.ca)
  • This graph shows the total number of publications written about "Ferredoxin-Nitrite Reductase" by people in this website by year, and whether "Ferredoxin-Nitrite Reductase" was a major or minor topic of these publications. (sickkids.ca)
  • Below are the most recent publications written about "Ferredoxin-Nitrite Reductase" by people in Profiles. (sickkids.ca)
  • Identification of the iron-sulfur center of spinach ferredoxin-nitrite reductase as a tetranuclear center, and preliminary EPR studies of mechanism. (duke.edu)
  • Cyanide binding to fully reduced Pseudomonas aeruginosa cd(1) nitrite reductase (Pa cd(1) NiR) has been investigated for the wild-type enzyme and a site-directed mutant in which the active-site His369 was replaced by Ala. This mutation reduces the affinity toward cyanide (by approximately 13-fold) and especially decreases the rate of binding of cyanide to the reduced d(1) heme (by approximately 100-fold). (rcsb.org)
  • After shifting an oxygen-respiring culture of Pseudomonas stutzeri to nitrate or nitrite respiration, we directly monitored the expression of the nirS gene by mRNA analysis. (asm.org)
  • The expression of denitrification in the strict sense is sequential in Pseudomonas stutzeri with respect to nitrate respiration, since activation of the narGHJI operon occurs at a higher partial oxygen pressure than that at which the other reductase genes are activated ( 24 , 25 ). (asm.org)
  • The periplasmic cytochrome cd 1 nitrite reductase NirS occurring in denitrifying bacteria such as the human pathogen Pseudomonas aeruginosa contains the essential tetrapyrrole cofactors haem c and haem d 1 . (portlandpress.com)
  • In the present paper, we summarize the current understanding of the reaction of nitrite reduction in the light of the most recent results on the enzyme from Pseudomonas aeruginosa and discuss the differences between enzymes from different organisms. (biochemsoctrans.org)
  • Wharton, DC & Weintraub, ST 1980, ' Identification of nitric oxide and nitrous oxide as products of nitrite reduction by Pseudomonas cytochrome oxidase (nitrite reductase) ', Topics in Catalysis , vol. 97, no. 1, pp. 236-242. (uthscsa.edu)
  • In enzymology, a nitrite reductase (NO-forming) (EC 1.7.2.1) is an enzyme that catalyzes the chemical reaction nitric oxide + H2O + ferricytochrome c ⇌ nitrite + ferrocytochrome c + 2 H+ The 3 substrates of this enzyme are nitric oxide, H2O, and ferricytochrome c, whereas its 3 products are nitrite, ferrocytochrome c, and H+. (wikipedia.org)
  • Lastly, since nrfA operon expression is only induced under low-nitrate concentrations, the NrfA enzyme is predicted to have a physiological role only where nitrate (or nitrite) is limiting in the cell environment. (asm.org)
  • The NirB nitrite reductase is a soluble siroheme-containing enzyme that uses NADH as an electron donor to reduce nitrite in the cytoplasm. (asm.org)
  • The NrfA nitrite reductase is a membrane-associated respiratory enzyme that couples to the membrane-associated formate-oxidizing enzymes via quinones in order to generate membrane potential. (asm.org)
  • The abundance of each enzyme is elevated during anaerobic cell growth conditions when either nitrate and/or nitrite is present ( 14 ). (asm.org)
  • Nitrite, the substrate for each enzyme, was shown to be a less potent regulatory signal for either operon relative to nitrate in contrast to prior reports. (asm.org)
  • This enzyme catalyzes the six-electron reduction of nitrite (NO 2 − ) to ammonia (NH 4 + ) ( 1 ) and its existence has been demonstrated in bacterial strains from almost every taxonomic branch. (pubmedcentralcanada.ca)
  • Both membrane nitrate reductase and nitrite reductase enzyme complexes were important for cytotoxicity during the interaction of P. aeruginosa PA14 with THP-1 cells. (asm.org)
  • Significant, well defined structural rearrangements in the active site are evident in the series as the enzyme moves through its catalytic cycle, namely nitrite reduction, which is a vital step in the global denitrification process. (rcsb.org)
  • The catalytic and spectral properties of the His-tagged, recombinant enzyme are similar, but not identical, to those previously observed for nitrite reductase isolated directly from spinach leaf. (elsevier.com)
  • A detailed comparison of the spectral, catalytic and fluorescence properties of nitrite reductase variants, in which each of the enzyme's eight tryptophan residues has been replaced using site-directed mutagenesis by either aromatic or non-aromatic amino acids, has been used to examine possible roles for tryptophan residues in the reduction of nitrite to ammonia catalyzed by the enzyme. (elsevier.com)
  • Hydroxylamine oxidoreductase (HAO), the AOB enzyme that catalyzes the 4-electron oxidation of hydroxylamine to nitrite, displays some structural commonalities towards the enzyme cytochrome nitrite reductase (ccNiR, also known as NrfA), which catalyzes the 6-electron reduced amount of nitrite to ammonia in ammonifying bacterias [3C10]. (neurokinin-receptor.info)
  • Nitrite reductase is an enzyme operating in the denitrification pathway which catalyses the conversion of nitrite (NO2(-)) to gaseous nitric oxide (NO). Here, crystal structures of the oxidized and reduced forms of the copper-containing nitrite reductase from Rhodobacter sphaeroides 2.4.3 are presented at 1.74 and 1.85 A resolution, respectively. (chalmers.se)
  • Whereas the structure of the enzyme is very similar to those of other copper-containing nitrite reductases, folding as a trimer and containing two copper sites per monomer, the structures reported here enable conformational differences between the oxidized and reduced forms of the enzyme to be identified. (chalmers.se)
  • Two sets of PCR primers have been designed to amplify fragments of the gene coding for nitric reductase, a key enzyme involved in bacterial denitrification. (readabstracts.com)
  • The enzyme also catalyzed the reduction of NO to N 2 O. No N 2 was identified as a consequence of either nitrite or NO reduction. (uthscsa.edu)
  • EPR spectroscopic and chemical analyses of spinach nitrite reductase show that the enzyme contains one reducible iron-sulfur center, and one site for binding either cyanide or nitrite, per siroheme. (duke.edu)
  • Complexation of the enzyme with CO (a known ligand for nitrite reductase heme) markedly increases the reducibility of the iron-sulfur center. (duke.edu)
  • The EPR spectrum of reduced nitrite reductase in 80% dimethyl sulfoxide establishes clearly that the enzyme contains a tetranuclear iron-sulfur (Fe4S4) center. (duke.edu)
  • This novel enzyme indicates (i) separate evolution of nitrite oxidation in " Ca . Nitrotoga" and other NOB, (ii) the possible existence of phylogenetically diverse, unrecognized NOB, and (iii) together with new metagenomic data, the potential existence of nitrite-oxidizing archaea. (asm.org)
  • This multiple heme-containing enzyme can reduce nitrite to ammonia. (jcvi.org)
  • 5.4 Test Method D7781 uses a nitrate reductase enzyme for the reduction of nitrate to nitrite. (astm.org)
  • We are also extending the target of our structural investigation to include the enzyme that prepares the siroheme for incorporation into sulfite reductase hemoprotein. (scripps.edu)
  • This enzyme, siroheme synthase, is required for expression of active sulfite reductase. (scripps.edu)
  • The cytochrome c nitrite reductase (ccNiR) from Desulfovibrio desulfuricans ATCC 27774 is able to reduce nitrite to ammonia in a six-electron transfer reaction. (pubmedcentralcanada.ca)
  • Cytochrome c nitrite reductase (ccNiR) is involved in the pathway called dissimilatory nitrate reduction to ammonia, thereby playing an important part in the biogeochemical nitrogen cycle. (pubmedcentralcanada.ca)
  • Ammonia oxidizers are a widespread and ecologically important group of bacteria that catalyze the oxidation of ammonia to nitrite (NO 2 − ) via hydroxylamine (NH 2 OH) in terrestrial, aquatic, and marine environments ( 5 ). (asm.org)
  • It catalyzes the six-electron oxidation of AMMONIA to nitrite. (sickkids.ca)
  • Interest in these intermediates is prompted by the presence of iron Cs or iBCs in enzymes that catalyze the reductions of nitrite to ammonia or nitric oxide (nitrite reductases) and the recent identification of cobalt iBC in sulfite reductases, enzymes which are also capable of nitrite reduction. (elsevier.com)
  • nitrite reductase, NrfA, Laue crystallography, UV/Vis spectropotentiometry, Proteins film voltammetry Launch Ammonia-nitrite interconversion, a significant area of the natural nitrogen cycle, is certainly completed by a number of bacterias within their respiratory procedure. (neurokinin-receptor.info)
  • In one path the ammonia oxidizing bacterias (AOB) such as for example make use of ammonia as an electron donor in respiration, and oxidize it to nitrite [1]. (neurokinin-receptor.info)
  • A different course of bacterias uses nitrite being a terminal electron acceptor in the lack of air, reducing it to ammonia in an activity referred to as nitrite ammonification [2]. (neurokinin-receptor.info)
  • CcNiR catalyzes the six-electron reduction of nitrite 870823-12-4 to ammonia (Plan 1, Eq. 1), as well as the five-electron reduction of nitric oxide (Plan 1, Eq. 2) and the two-electron reduction of hydroxylamine (Plan 1, Eq. 3) to ammonia [11, 14]. (neurokinin-receptor.info)
  • Dissimilatory nitrate reduction to ammonia (DNRA) is the process in which nitrate is reduced, via nitrite, to ammonia. (warwick.ac.uk)
  • Polysulphide reductase, NrfD RN [1] RM PMID: 8057835 RT A seven-gene operon essential for formate-dependent nitrite reduction to ammonia by enteric bacteria. (jcvi.org)
  • We used multiwavelength anomalous diffraction of the native siroheme and Fe 4 S 4 cluster cofactors to solve the atomic resolution structure of sulfite reductase hemoprotein, which catalyzes the concerted 6-electron reductions of sulfite to sulfide and nitrite to ammonia. (scripps.edu)
  • Sulfite reductase catalyzes the concerted 6-electron reductions of sulfite to sulfide and nitrite to ammonia. (scripps.edu)
  • nirS encodes the 62-kDa subunit of the homodimeric cytochrome cd 1 nitrite reductase involved in denitrification. (asm.org)
  • Our results suggest that a nitrate- and nitrite-responsive regulatory circuit independent of NarXL is necessary for the activation of denitrification genes. (asm.org)
  • In the present study, we investigated the signal and regulator requirements for the transcriptional activation of nirS , norCB , and nosZ (i.e., the structural genes for the three reductases involved in nitrite denitrification) following a shifting of the respiratory metabolism from oxygen to nitrate or nitrite. (asm.org)
  • By studying narX and narL deletion mutants, we obtained evidence for the existence of a second nitrate- and nitrite-responsive regulatory system in P. stutzeri that is specific for denitrification. (asm.org)
  • The cytochrome cd 1 nitrite reductases are enzymes that catalyse the reduction of nitrite to nitric oxide (NO) in the bacterial energy conversion denitrification process. (biochemsoctrans.org)
  • Strains lacking genes required for a functional nitrate reductase had decreased fitness as both metals interacted with heme-containing enzymes required for the later steps in the denitrification pathway after nitrate is reduced to nitrite. (frontiersin.org)
  • The association with plants affects expression of denitrification genes, the regulation of nitrite and nitric oxide reductases was investigated in Agrobacterium tumefaciens. (readabstracts.com)
  • It reduces nitrite to nitric oxide, the first step in denitrification. (nih.gov)
  • The goal of this project is to compare the distribution, diversity, and expression of denitrification genes (nitrite reductase) from microorganisms in the two lobes in an attempt to explain this mystery. (nsf.gov)
  • Test Methods D3867 uses cadmium for the reduction of nitrate to nitrite. (astm.org)
  • The inter- and intra-electron and proton transfers in the nitrite reduction of copper-containing nitrite reductase (CuNiR) were investigated by using the QM/MM method with the calculational models containing type 1 (T1) and type 2 (T2) Cu sites. (rsc.org)
  • The electron transfer from the outer electron donor protein to the T1 Cu site occurred both before and after nitrite binding, and nitrite binding lowered the reduction potential of the Cu T1 site. (rsc.org)
  • The protonation of catalytic His244 subsequent to nitrite binding and T1 Cu reduction induced partial intra-electron transfer from T1 to T2 Cu sites. (rsc.org)
  • Nitrite, the substrate for the two enzymes, must either be encountered environmentally or generated by the cell from nitrate reduction by one of the three E. coli nitrate reductases. (asm.org)
  • Solution assays have proved that the specific activity of ccNiR decreases with the reduction potential of the electronic carriers and ammonium is always the main product of nitrite reduction. (pubmedcentralcanada.ca)
  • One axial position of the iron atom is occupied by a histidine and the second one is the place of the nitrite reduction. (fu-berlin.de)
  • The nirK gene of Rhizobium hedysari HCNT1 encodes nitrite reductase, and the reduction of nitrite causes the production of large concentrations of freely diffusible nitric oxide (NO). The nitrite reductase is structurally similar to the copper containing family of nitrite reductases. (readabstracts.com)
  • The bacteria is unable to link nitrite reduction to energy conservation, and the amount of NO it produces is much higher than that produced by other denitrifiers. (readabstracts.com)
  • Does the reduction of c heme trigger the conformational change of crystalline nitrite reductase? (expasy.org)
  • This serial crystallography approach revealed the gradual conversion of the substrate bound at the catalytic type 2 Cu centre from nitrite to nitric oxide, following reduction of the type 1 Cu electron-transfer centre by X-ray-generated solvated electrons. (rcsb.org)
  • These findings shed light on the structural mechanism of the reduction of a copper-bound nitrite to nitric oxide and water. (chalmers.se)
  • The reduction of nitrite to NO involves binding of nitrite to the reduced protein at the level of d1-heme, followed by dehydration of nitrite to yield NO and release of the latter. (unicatt.it)
  • Pseudoazurin (Paz) is the physiological electron donor to copper-containing nitrite reductase (Nir), which catalyzes the reduction of NO2− to NO. The Nir reaction mechanism involves the reduction of the type 1 (T1) copper electron transfer center by the external physiological electron donor, intramolecular electron transfer from the T1 copper center to the T2 copper center, and nitrite reduction at the type 2 (T2) copper catalytic center. (conicet.gov.ar)
  • EPR experiments proved that as a result of the SmPaz/SmNir interaction in the presence of nitrite, the order of the reduction potentials of SmNir reversed, in line with T1 center to T2 center electron transfer being thermodynamically more favorable. (conicet.gov.ar)
  • The pentaheme cytochrome c nitrite reductase (NrfA) of Escherichia coli is responsible for nitrite reduction during anaerobic respiration when nitrate is scarce. (uea.ac.uk)
  • Both NO and N 2 O were identified by GC/MS as gaseous products of nitrite reduction catalyzed by the cytochrome oxidase (nitrite reductase) purified from Pseudomonasaeruginosa. (uthscsa.edu)
  • No N2 was identified as a consequence of either nitrite or NO reduction. (uthscsa.edu)
  • RT "Location and sequence of the promoter of the gene for the NADH- RT dependent nitrite reductase of Escherichia coli and its regulation by RT oxygen, the Fnr protein and nitrite. (genome.jp)
  • Escherichia coli possesses two distinct nitrite reductase enzymes encoded by the nrfA and nirB operons. (asm.org)
  • Escherichia coli possesses two biochemically distinct nitrite reductase enzymes encoded by the nrfABCDEFG and nirBDC operons ( 4 ). (asm.org)
  • A system has been developed for expressing a His-tagged form of the ferredoxin-dependent nitrite reductase of spinach in Escherichia coli. (elsevier.com)
  • Complementary DNA has been isolated that codes for maize nitrite reductase (NiR) by using the corresponding spinach gene (E Back et al . (plantphysiol.org)
  • A high percentage of the differences in the DNA sequences is due to the extremely strong bias in the corn gene to have a G/C base in the third codon position with 559/569 codons ending in a G or C. Using a hydroponic system, maize seedlings grown in the absence of an exogenous nitrogen source were induced with nitrate or nitrite. (plantphysiol.org)
  • There is also a considerable induction of this gene in roots upon the addition of nitrite, although under the conditions used the final mRNA level was not as high as when nitrate was the inducer. (plantphysiol.org)
  • We previously found that the transcript level of the nitrite reductase gene of F. oxysporum , named FoNIIA , was markedly upregulated during conidiation compared with during vegetative growth. (apsnet.org)
  • Steady-state gene expression studies revealed a differential pattern of nitrite reductase gene expression where optimal nrfA-lacZ expression occurred only at low to intermediate levels of nitrate and where nirB-lacZ expression was induced only by high nitrate conditions. (asm.org)
  • It is unknown how the nrfA and nirB operons are expressed in response to either low or intermediate levels of either nitrate or nitrite since the prior gene regulation studies were performed in batch cultures using high levels of each anion. (asm.org)
  • The findings reveal a differential pattern of nitrite reductase gene expression whereby the nrfA operon is preferentially expressed only at low nitrate concentrations. (asm.org)
  • Similar mRNA stability and transition kinetics were observed for the norCB operon, encoding the NO reductase complex, and the nosZ gene, encoding nitrous oxide reductase. (asm.org)
  • Global gene expression was compared between the Nitrosomonas europaea wild type and a nitrite reductase-deficient mutant using a genomic microarray. (asm.org)
  • The gene for a homologue to dissimilatory nitrite reductase, nirK , is present at the end of a four-gene cluster in Nitrosomonas europaea ( 7 ). (asm.org)
  • Copper-containing nitrite reductases (CuNiRs), encoded by nirK gene, are found in all kingdoms of life with only 5% of CuNiR denitrifiers having two or more copies of nirK . (sciencemag.org)
  • Nitrate, nitrite, nitric oxide and nitrous oxide reducing activities were expressed, and the structural genes for nitrite and nitric oxide reductases were transcribed under anaerobic conditions in the anr mutant strain transformed with the dnr gene. (nih.gov)
  • Consensus regions in gene sequences encoding the two forms of nitrite reductase, cd(sub 1)-nir and Cu-nir were used in the preparation of the primers. (readabstracts.com)
  • Molecular cloning, characterization, and nucleotide sequence of nit-6, the structural gene for nitrite reductase in Neurospora crassa. (genome.jp)
  • Cytochrome c Nitrite Reductase from Desulfovibrio desulfuricans ATCC 27774: The relevance of the two calcium sites in the structure of the catalytic subunit (NrfA). (expasy.org)
  • Members of this protein family are NrfD, a highly hydrophobic protein encoded in the nrf operon, which encodes cytochrome c nitrite reductase. (jcvi.org)
  • Ancestral nitric oxide reductases, as well as cytochrome c oxidases and quinol bo oxidases evolved from the former, are capable of binding and detoxifying nitric oxide to nitrous oxide. (elsevier.com)
  • Vázquez-Torres, A & Baumler, AJ 2016, ' Nitrate, nitrite and nitric oxide reductases: From the last universal common ancestor to modern bacterial pathogens ', Current Opinion in Microbiology , vol. 29, 1395, pp. 1-8. (elsevier.com)
  • These results shed light on the mechanistic details of the activity of cd 1 nitrite reductases and on the biological role of the d 1 -haem, whose presence in this class of enzymes has to date been unexplained. (biochemsoctrans.org)
  • In aerobic soils, nitrate is the dominant species and it is converted to ammonium by the sequential action of two enzymes, nitrate reductase (NR) and nitrite reductase (NiR) (Dechorgnat et al. (thefreelibrary.com)
  • Members belong to a broader PFAM protein family, PF03916, which also contains an NrfD-related subunit of polysulphide reductase. (jcvi.org)
  • norC and norB encode the cytochrome-c-containing subunit II and cytochrome b-containing subunit I of nitric-oxide reductase (NO reductase), respectively. (tcdb.org)
  • Each NOS subunit is divided into 2 domains joined by a calmodulin-binding hinge region: (1) an oxygenase domain with binding sites for heme, tetrahydrobiopterin, and substrate that forms the catalytic center for production of nitric oxide and (2) a reductase domain with binding sites for NADPH, FAD, and FMN that supplies electrons to the oxygenase domain. (scripps.edu)
  • The continued transcription of the nirS operon required the presence of nitrate or nitrite. (asm.org)
  • By monitoring the production of narH and nirS transcripts of Paracoccus denitrificans , it has been shown that induction of nitrate reductase precedes that of nitrite reductase ( 8 ). (asm.org)
  • Furthermore, deletion mutations in genes encoding membrane nitrate reductase (Δ narGH ) and nitrite reductase (Δ nirS ) produced defects in the expression of type III secretion system (T3SS) components, extracellular protease, and elastase. (asm.org)
  • Addition of exogenous nitric oxide (NO)-generating compounds to Δ nirS mutant cultures restored the production of T3SS phospholipase ExoU, whereas nitrite addition had no effect. (asm.org)
  • These data suggest that NO generated via nitrite reductase NirS contributes to the regulation of expression of selected virulence factors in P. aeruginosa PA14. (asm.org)
  • Knaff, David B. / The role of tryptophan in the ferredoxin-dependent nitrite reductase of spinach . (elsevier.com)
  • Atomic resolution structures of resting-state, substrate- and product-complexed Cu-nitrite reductase provide insight into catalytic mechanism. (ebi.ac.uk)
  • Nitrite oxidation followed Michaelis-Menten kinetics, with an apparent K m ( K m (app) ) of ~89 µM nitrite and a V max of ~28 µmol of nitrite per mg of protein per h. (asm.org)
  • Dr. McCarthy's recent work produced a nitrate reductase mutant strain of P. tricornutum , described how the loss of function affected the morphology and viability of the cell and pointed to physiological and molecular mechanisms that drive vacuolar storage of nitrate and the possibility of nitrate reductase-vacuolar transport protein complexes. (jcvi.org)
  • It is unknown which N -oxide-sensitive regulatory system controls the genes encoding the reductases of denitrifying bacteria that act on the substrates nitrite, nitric oxide, and nitrous oxide and to what extent their activation depends on coordinately and/or sequentially acting regulators. (asm.org)
  • Ca . Nitrotoga fabula" possesses a new type of periplasmic nitrite oxidoreductase belonging to a lineage of mostly uncharacterized proteins. (asm.org)
  • These chlorotic plants strongly resemble those transformed with a 35S-Nii (nitrite reductase) transgene, in which both Nii host genes and the 35S-Nii transgene are silenced by co-suppression. (deepdyve.com)
  • reductase) transgene, in which both Nii host genes and the 35S- Nii transgene are silenced by co-suppressi on. (deepdyve.com)
  • The proton transfer from His244 to nitrite bound on the T2 Cu site via the hydrogen bond network induced intra-electron transfer from the T1 to T2 Cu site. (rsc.org)
  • The expression of each operon is induced during anaerobic cell growth conditions and is further modulated by the presence of either nitrite or nitrate in the cells' environment. (asm.org)
  • To examine how each operon is expressed at low, intermediate, and high levels of either nitrate or nitrite, anaerobic chemostat culture techniques were employed using nrfA-lacZ and nirB-lacZ reporter fusions. (asm.org)
  • Thus, we examined the steady-state expression of nrfA-lacZ and nirB-lacZ reporter fusions using anaerobic chemostat culture methods under limiting nitrite or nitrate conditions. (asm.org)
  • NO detoxification by NO reductase during anaerobic growth is therefore important for maintenance of cell function. (asm.org)
  • Molecular characterization of a copper-containing nitrite reductase from Rhodopseudomonas sphaeriodes forma sp. (wikipedia.org)
  • Here, we explore this idea in a tethered 3-domain, trimeric copper-containing nitrite reductase. (nih.gov)
  • Rationale and strategy for studying the role of redox partner tethering in copper containing nitrite reductase. (nih.gov)
  • top) and proposed mechanism (bottom) of the 3-domain copper containing nitrite reductase, Rp NiR, used in this study. (nih.gov)
  • Recent structural insights into the function of copper nitrite reductases. (ebi.ac.uk)
  • Rapid, shutterless X-ray detector technology on a synchrotron MX beamline was exploited to perform low-dose serial crystallography on a single copper nitrite reductase crystal, which survived long enough for 45 consecutive 100 K X-ray structures to be collected at 1.07-1.62 Å resolution, all sampled from the same crystal volume. (rcsb.org)
  • This family consists of copper-type nitrite reductase. (nih.gov)
  • Copper-containing nitrite reductase harbors a type-1 and a type-2 Cu site. (forskningsdatabasen.dk)
  • 1.1 This test method is applicable to the determination of nitrate plus nitrite (as nitrogen) in drinking water, surface, saline, wastewater, and ground waters. (astm.org)
  • From the 1940s to the 1970s, several studies indicated that a microbe was missing from nature that could anaerobically oxidize ammonium, with nitrate or nitrite, to dinitrogen gas and that the nitrogen cycle ( Fig. 1 ) thus contained more reactions than was known at that time ( 8 , 29 , 73 ). (asm.org)
  • 1.1 These test methods cover the determination of nitrite nitrogen, nitrate nitrogen, and combined nitrite-nitrate nitrogen in water and wastewater in the range from 0.05 to 1.0 mg/L nitrogen. (astm.org)
  • Sulfite and nitrite reductases catalyze fundamental chemical transformations for biogeochemical cycling of sulfur and nitrogen. (scripps.edu)
  • The addition of nitrite, but not nitrate, is reported to further elevate nrfA expression via either the NarL or NarP response regulators. (asm.org)
  • Thus, revised models for the control of the nrfA and nirB nitrite reductase operons are proposed. (asm.org)
  • Recently, the structure of a Cu-containing nitrite reductase (NiR) from Hyphomicrobium denitrificans ( Hd NiR) has been reported, establishing the existence of a new family of Cu-NiR where an additional type 1 Cu (T1Cu) containing cupredoxin domain is located at the N-terminus (Nojiri et al. (springer.com)
  • We have evidence that release of NO from the ferrous d 1 -haem occurs rapidly enough to be fully compatible with the turnover, in contrast with previous hypotheses, and that the substrate nitrite is able to displace NO from the d 1 -haem iron. (biochemsoctrans.org)
  • Nitrite reductase and NO reductase (with succinate or ascorbate as substrates) and nitrous oxide reductase (with succinate as substrate) activities were not detected in these mutant strains. (tcdb.org)
  • The electrochemical gradient that ensues from the enzymatic activity of cytochromes such as nitrate reductase, nitric oxide reductase, and quinol oxidase contributes to the bioenergetics of the bacterial cell. (elsevier.com)
  • The finally formed NO (in this particular bacterial nitrite reductase) is replaced by a hydroxo ligand. (fu-berlin.de)
  • The heme-containing periplasmic nitrite reductase (cd1 NIR) is responsible for the production of nitric oxide (NO) in denitrifying bacterial species, among which are several animal and plant pathogens. (unicatt.it)
  • In addition to nitrite, some ccNiRs were shown to reduce other substrates like nitric oxide, hydroxylamine, o-methylhydroxylamine [ 6 ], or sulphite [ 7 , 8 ]. (pubmedcentralcanada.ca)
  • Mutation of this glutamine to the more usual calcium ligand, glutamate, results in an increase in the Km for nitrite by around 10-fold, while Vmax is unaltered. (uea.ac.uk)
  • We determined 12 key high-resolution structures of sulfite reductase hemoprotein that characterize its active center in 3 different states of oxidation and its interactions with substrates, inhibitors, intermediates, and products. (scripps.edu)
  • We used multiwavelength anomalous diffraction of the native siroheme, an iron-containing macrocycle of the isobacteriochlorin class, and Fe 4 S 4 cluster cofactors to solve the atomic-resolution structure of the hemoprotein from sulfite reductase hemoprotein. (scripps.edu)
  • In contrast, the nirB nitrite reductase is optimally synthesized only when nitrate or nitrite is in excess of the cell's capacity to consume it. (asm.org)
  • In contrast, only NarL is reported to activate nirB in response to nitrite ( 23 , 24 ). (asm.org)
  • The high-yield expression and purification of cytochrome nitrite reductase (ccNiR), and its own characterization by a variety of methods, notably Laue crystallography, is reported. (neurokinin-receptor.info)
  • Effect of inhibition of the Hill reaction on polyribosomes level and on induced synthesis of nitrate and nitrite reductases in rice seedlings. (bvsalud.org)
  • Some properties of nitrate and nitrite reductases from rice seedlings. (bvsalud.org)
  • It transfers electrons between Complexes III (Coenzyme Q - Cyt C reductase) and IV (Cyt C oxidase). (wikipedia.org)

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