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Pesquisa : D08.811.682.655.500.249 [Categoria DeCS]
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  1 / 25 MEDLINE  
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[PMID]:19919002
[Au] Autor:Taveirne ME; Sikes ML; Olson JW
[Ad] Endereço:Department of Microbiology, North Carolina State University, Raleigh, NC 27695, USA.
[Ti] Título:Molybdenum and tungsten in Campylobacter jejuni: their physiological role and identification of separate transporters regulated by a single ModE-like protein.
[So] Source:Mol Microbiol;74(3):758-71, 2009 Nov.
[Is] ISSN:1365-2958
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Campylobacter jejuni is an important human pathogen that causes millions of cases of food-borne enteritis each year. The C. jejuni respiratory chain is highly branched and contains at least four enzymes predicted to contain a metal binding pterin (MPT), with the metal being either molybdenum or tungsten. Also predicted are two separate transport systems, one for molybdenum encoded by modABC and a second for tungsten encoded by tupABC. Both transport systems were mutated and the activities of the four predicted MPT-containing enzymes were assayed in the presence of molybdenum and tungsten in wild-type and mod and tup backgrounds. Results indicate that mod is primarily a molybdenum transporter that can also transport tungsten, while tup is a tungsten-specific transporter. The MPT containing enzymes nitrate reductase, sulphite oxidase, and SN oxide reductase are strict molybdoenzymes while formate dehydrogenase prefers tungsten. A ModE-like protein regulates both transporters, repressing mod in the presence of both molybdenum and tungsten and tup only in the presence of tungsten. Like other ModE proteins, the C. jejuni ModE binds DNA through a helix-turn-helix DNA binding domain, but unlike other members of the ModE family it does not have a metal binding domain.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Campylobacter jejuni/metabolismo
Proteínas de Membrana Transportadoras/metabolismo
Molibdênio/metabolismo
Fatores de Transcrição/metabolismo
Tungstênio/metabolismo
[Mh] Termos MeSH secundário: Transportadores de Cassetes de Ligação de ATP/genética
Transportadores de Cassetes de Ligação de ATP/metabolismo
Sequência de Aminoácidos
Proteínas de Bactérias/genética
Campylobacter jejuni/genética
Transporte de Elétrons/genética
Escherichia coli/genética
Escherichia coli/metabolismo
Formiato Desidrogenases/genética
Formiato Desidrogenases/metabolismo
Seres Humanos
Proteínas de Membrana Transportadoras/genética
Dados de Sequência Molecular
Molibdênio/química
Nitrato Redutase/genética
Nitrato Redutase/metabolismo
Nitrato Redutase (NAD(P)H)/metabolismo
Nitrato Redutases/química
Nitrato Redutases/genética
Nitrato Redutases/metabolismo
Filogenia
Engenharia de Proteínas
Pterinas/metabolismo
Alinhamento de Sequência
Homologia de Sequência de Aminoácidos
Tungstênio/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Membrane Transport Proteins); 0 (ModE protein, bacteria); 0 (Pterins); 0 (Transcription Factors); 81AH48963U (Molybdenum); EC 1.2.1.2 (Formate Dehydrogenases); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H)); EC 1.7.99.4 (Nitrate Reductase); V9306CXO6G (Tungsten)
[Em] Mês de entrada:1003
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:091118
[St] Status:MEDLINE


  2 / 25 MEDLINE  
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Texto completo
[PMID]:18188019
[Au] Autor:Dharajiya N; Boldogh I; Cardenas V; Sur S
[Ad] Endereço:NHLBI Proteomics Center, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555-1083, USA.
[Ti] Título:Role of pollen NAD(P)H oxidase in allergic inflammation.
[So] Source:Curr Opin Allergy Clin Immunol;8(1):57-62, 2008 Feb.
[Is] ISSN:1528-4050
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE OF REVIEW: Plant pollens are one of the most common outdoor allergens. Pollen grains and subpollen particles can reach lower airways and induce symptoms of seasonal asthma and allergic rhinitis. Plants possess NAD(P)H oxidase activity that generates reactive oxygen species for physiological functions such as root-hair and pollen-tube growth, defense against microbial infections and cell signaling. The presence of NAD(P)H oxidases in pollens and their role in induction of airway inflammation have not been described until recently. RECENT FINDINGS: We discovered the presence of NAD(P)H oxidase in ragweed and other plant pollens. These oxidases induce reactive oxygen species in mucosal cells (signal 1) independent of adaptive immunity. This reactive oxygen species facilitates antigen (signal 2)-induced allergic inflammation. Inhibiting signal 1 by administration of antioxidants attenuated ragweed extract-induced allergic inflammation. Likewise, abrogating signal 2 by antigen challenge in mice lacking T cells failed to induce allergic inflammation. SUMMARY: Reactive oxygen species generated by pollen NAD(P)H oxidase play a major role in pathogenesis of allergic airway inflammation and airway hypersensitivity. Based on our findings, we propose a 'two signal hypothesis of allergic inflammation' in which both signal 1 (reactive oxygen species) and signal 2 (antigen presentation) are required in order to induce full-blown allergic inflammation.
[Mh] Termos MeSH primário: Alérgenos
Ambrosia/enzimologia
Nitrato Redutase (NAD(P)H)/imunologia
Pólen/enzimologia
Hipersensibilidade Respiratória/imunologia
[Mh] Termos MeSH secundário: Alérgenos/imunologia
Ambrosia/imunologia
Animais
Apresentação do Antígeno
Antioxidantes/uso terapêutico
Asma/imunologia
Seres Humanos
Hipersensibilidade Imediata/imunologia
Imunidade nas Mucosas
Camundongos
Modelos Imunológicos
Nitrato Redutase (NAD(P)H)/metabolismo
Pólen/imunologia
Espécies Reativas de Oxigênio/imunologia
Hipersensibilidade Respiratória/fisiopatologia
Hipersensibilidade Respiratória/terapia
Rinite Alérgica Sazonal/imunologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; REVIEW
[Nm] Nome de substância:
0 (Allergens); 0 (Antioxidants); 0 (Reactive Oxygen Species); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H))
[Em] Mês de entrada:0805
[Cu] Atualização por classe:161203
[Lr] Data última revisão:
161203
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:080112
[St] Status:MEDLINE
[do] DOI:10.1097/ACI.0b013e3282f3b5dc


  3 / 25 MEDLINE  
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[PMID]:17336614
[Au] Autor:Dharajiya N; Choudhury BK; Bacsi A; Boldogh I; Alam R; Sur S
[Ad] Endereço:National Heart, Lung, and Blood Institute Proteomics Center, University of Texas Medical Branch, Division of Allergy and Immunology, Department of Internal Medicine, Galveston, Texas, USA.
[Ti] Título:Inhibiting pollen reduced nicotinamide adenine dinucleotide phosphate oxidase-induced signal by intrapulmonary administration of antioxidants blocks allergic airway inflammation.
[So] Source:J Allergy Clin Immunol;119(3):646-53, 2007 Mar.
[Is] ISSN:0091-6749
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Ragweed extract (RWE) contains NADPH oxidases that induce oxidative stress in the airways independent of adaptive immunity (signal 1) and augment antigen (signal 2)-induced allergic airway inflammation. OBJECTIVE: To test whether inhibiting signal 1 by administering antioxidants inhibits allergic airway inflammation in mice. METHODS: The ability of ascorbic acid (AA), N-acetyl cystenine (NAC), and tocopherol to scavenge pollen NADPH oxidase-generated reactive oxygen species (ROS) was measured. These antioxidants were administered locally to inhibit signal 1 in the airways of RWE-sensitized mice. Recruitment of inflammatory cells, mucin production, calcium-activated chloride channel 3, IL-4, and IL-13 mRNA expression was quantified in the lungs. RESULTS: Antioxidants inhibited ROS generation by pollen NADPH oxidases and intracellular ROS generation in cultured epithelial cells. AA in combination with NAC or Tocopherol decreased RWE-induced ROS levels in cultured bronchial epithelial cells. Coadministration of antioxidants with RWE challenge inhibited 4-hydroxynonenal adduct formation, upregulation of Clca3 and IL-4 in lungs, mucin production, recruitment of eosinophils, and total inflammatory cells into the airways. Administration of antioxidants with a second RWE challenge also inhibited airway inflammation. However, administration of AA+NAC 4 or 24 hours after RWE challenge failed to inhibit allergic inflammation. CONCLUSION: Signal 1 plays a proinflammatory role during repeated exposure to pollen extract. We propose that inhibiting signal 1 by increasing antioxidant potential in the airways may be a novel therapeutic strategy to attenuate pollen-induced allergic airway inflammation. CLINICAL IMPLICATIONS: Administration of antioxidants in the airways may constitute a novel therapeutic strategy to prevent pollen induced allergic airway inflammation.
[Mh] Termos MeSH primário: Antioxidantes/administração & dosagem
Bronquite/prevenção & controle
Hipersensibilidade/prevenção & controle
Nitrato Redutase (NAD(P)H)/toxicidade
Pólen/imunologia
[Mh] Termos MeSH secundário: Acetilcisteína/administração & dosagem
Administração por Inalação
Animais
Ácido Ascórbico/administração & dosagem
Canais de Cloreto/análise
Canais de Cloreto/metabolismo
Interleucina-13/análise
Interleucina-13/metabolismo
Interleucina-4/análise
Interleucina-4/metabolismo
Pulmão/química
Pulmão/imunologia
Camundongos
Mucinas/análise
Mucinas/metabolismo
Nitrato Redutase (NAD(P)H)/antagonistas & inibidores
Extratos Vegetais/toxicidade
Pólen/enzimologia
Espécies Reativas de Oxigênio/antagonistas & inibidores
Tocoferóis/administração & dosagem
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Antioxidants); 0 (Chloride Channels); 0 (Interleukin-13); 0 (Mucins); 0 (Plant Extracts); 0 (Reactive Oxygen Species); 207137-56-2 (Interleukin-4); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H)); PQ6CK8PD0R (Ascorbic Acid); R0ZB2556P8 (Tocopherols); WYQ7N0BPYC (Acetylcysteine)
[Em] Mês de entrada:0704
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:070306
[St] Status:MEDLINE


  4 / 25 MEDLINE  
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[PMID]:16097946
[Au] Autor:Morozkina EV; Nosikov AN; Zvyagilskaya RA; L'vov NP
[Ad] Endereço:Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 119071, Russia. Chicelena@pisem.net
[Ti] Título:Isolation, purification, and characterization of nitrate reductase from a salt-tolerant Rhodotorula glutinis yeast strain grown in the presence of tungsten.
[So] Source:Biochemistry (Mosc);70(7):809-14, 2005 Jul.
[Is] ISSN:0006-2979
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The salt-tolerant Rhodotorula glutinis yeast strain grew in medium containing nitrate, 1 mM tungsten, and trace amounts of molybdenum (as impurities from the reagents used). Isolation of electrophoretically homogenous preparation of nitrate reductase from the Rh. glutinis cells grown under these growth conditions is described. The isolated nitrate reductase is a molybdenum-containing homodimer with molecular mass of 130 kD, containing 0.177 mol of Mo per mol of the enzyme. The activity of the enzyme is maximal at pH 7.0 and 35-45 degrees C and is inhibited by low concentrations of azide and cyanide. The enzyme is almost insensitive to 1 mM tungsten.
[Mh] Termos MeSH primário: Nitrato Redutase (NAD(P)H)/química
Nitrato Redutase (NAD(P)H)/isolamento & purificação
Rhodotorula/enzimologia
Rhodotorula/crescimento & desenvolvimento
Sais/química
Tungstênio/farmacologia
[Mh] Termos MeSH secundário: Azidas/farmacologia
Cianetos/farmacologia
Relação Dose-Resposta a Droga
Concentração de Íons de Hidrogênio
Peso Molecular
Molibdênio/química
Molibdênio/farmacologia
Nitratos/química
Nitratos/farmacologia
Rhodotorula/efeitos dos fármacos
Relação Estrutura-Atividade
Temperatura Ambiente
Tungstênio/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Azides); 0 (Cyanides); 0 (Nitrates); 0 (Salts); 81AH48963U (Molybdenum); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H)); V9306CXO6G (Tungsten)
[Em] Mês de entrada:0601
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:050816
[St] Status:MEDLINE


  5 / 25 MEDLINE  
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[PMID]:12927686
[Au] Autor:Dziedzic B; Mazanowska-Gajdowicz J; Walczewska A; Sarniak A; Nowak D
[Ad] Endereço:Department of Experimental and Clinical Physiology, Institute of Biochemistry and Physiology, Medical University of Lodz, Mazowiecka 6/8, Lodz 92-215, Poland.
[Ti] Título:Comparison of cadmium and enzyme-catalyzed nitrate reduction for determination of NO2-/NO3- in breath condensate.
[So] Source:Clin Chim Acta;335(1-2):65-74, 2003 Sep.
[Is] ISSN:0009-8981
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Analysis of NO2-/NO3- in expired breath condensate (EBC) has been proposed as a marker of inflammation in various lung diseases. METHODS: NO2- and total NO3-/NO2- concentrations were determined in EBC collected from healthy and asthmatic subjects. The NO3- was first reduced to NO2-, and total NO2- was detected by colorimetric Griess reaction. Two methods of NO3- reduction were compared. To reduce NO3-, cadmium (600 microl EBC-macromethod) and enzyme-NADPH-nitrate reductase (60 microl EBC-micromethod) were used. RESULTS: Macromethod: Mean NO2- concentrations in EBC were 1.64 +/- 0.24 micromol/l in healthy subjects and 0.42 +/- 0.17 micromol/l in asthmatic patients. Mean total NO2-/NO3- levels were 3.64 +/- 0.43 micromol/l in healthy subjects and 3.27 +/- 0.34 micromol/l in asthmatic. Micromethod: NO2- level: 1.69 +/- 0.23 micromol/l in healthy subjects and 0.53 +/- 0.21 micromol/l in asthmatics. Total NO2-/NO3- levels: 3.56 +/- 0.37 micromol/l in healthy subjects and 3.57 +/- 1.17 micromol/l in asthmatics. Variability index was 27% and 6% for macro- and micromethod, respectively. Recovery of NO3- added to EBC was 100% for enzymatic and almost 88% for cadmium reduction. There was no correlation between total NO2-/NO3- levels determined by macro- and micromethod. CONCLUSIONS: We recommend enzymatic reduction as a better method for NO3- determination in EBC.
[Mh] Termos MeSH primário: Testes Respiratórios/métodos
Cádmio/metabolismo
Nitrato Redutases/metabolismo
Nitratos/análise
Nitritos/análise
[Mh] Termos MeSH secundário: Adulto
Biomarcadores/análise
Estudos de Casos e Controles
Catálise
Feminino
Seres Humanos
Masculino
Meia-Idade
Nitrato Redutase (NAD(P)H)
Oxirredução
[Pt] Tipo de publicação:COMPARATIVE STUDY; EVALUATION STUDIES; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Biomarkers); 0 (Nitrates); 0 (Nitrites); 00BH33GNGH (Cadmium); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H))
[Em] Mês de entrada:0404
[Cu] Atualização por classe:151119
[Lr] Data última revisão:
151119
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:030821
[St] Status:MEDLINE


  6 / 25 MEDLINE  
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[PMID]:12141490
[Au] Autor:Bhushan B; Halasz A; Spain J; Thiboutot S; Ampleman G; Hawari J
[Ad] Endereço:Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec.
[Ti] Título:Biotransformation of hexahydro-1,3,5-trinitro-1,3,5-tiazine catalyzed by a NAD(P)H: nitrate oxidoreductase from Aspergillus niger.
[So] Source:Environ Sci Technol;36(14):3104-8, 2002 Jul 15.
[Is] ISSN:0013-936X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) can be efficiently mineralized with anaerobic domestic sludge, but the initial enzymatic processes involved in its transformation are unknown. To test the hypothesis that the initial reaction involves reduction of nitro group(s), we designed experiments to test the ability of a nitrate reductase (EC 1.6.6.2) to catalyze the initial reaction leading to ring cleavage and subsequent decomposition. A nitrate reductase from Aspergillus niger catalyzed the biotransformation of RDX most effectively at pH 7.0 and 30 degrees C under anaerobic conditions using NADPH as electron donor. LC/MS (ES-) chromatograms showed the formation of hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) and methylenedinitramine as key initial products of RDX, but neither the dinitroso neither (DNX) nor trinitroso (TNX) derivatives were observed. None of the above detected products persisted, and their disappearance was accompanied by the accumulation of nitrous oxide (N20), formaldehyde (HCHO), and ammonium ion (NH4+). Stoichiometric studies showed that three NADPH molecules were consumed, and one molecule of methylenedinitramine was produced per RDX molecule. The carbon and nitrogen mass balances were 96.14% and 82.10%, respectively. The stoichiometries and mass balance measurements supported a mechanism involving initial transformation of RDX to MNX via a two-electron reduction mechanism. Subsequent reduction of MNX followed by rapid ring cleavage gave methylenedinitramine which in turn decomposed in water to produce quantitatively N2O and HCHO. The results clearly indicate that an initial reduction of a nitro group by nitrate reductase is sufficient for the decomposition of RDX.
[Mh] Termos MeSH primário: Aspergillus niger/enzimologia
Nitrato Redutases/farmacologia
Rodenticidas/metabolismo
Triazinas/metabolismo
[Mh] Termos MeSH secundário: Biotransformação
Poluentes Ambientais/metabolismo
Concentração de Íons de Hidrogênio
Nitrato Redutase (NAD(P)H)
Esgotos/química
Esgotos/microbiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Environmental Pollutants); 0 (Rodenticides); 0 (Sewage); 0 (Triazines); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H)); W91SSV5831 (cyclonite)
[Em] Mês de entrada:0301
[Cu] Atualização por classe:121115
[Lr] Data última revisão:
121115
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:020727
[St] Status:MEDLINE


  7 / 25 MEDLINE  
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[PMID]:12139973
[Au] Autor:Pollock VV; Conover RC; Johnson MK; Barber MJ
[Ad] Endereço:Department of Biochemistry and Molecular Biology, College of Medicine, University of South Florida, Tampa, FL 33612, USA.
[Ti] Título:Bacterial expression of the molybdenum domain of assimilatory nitrate reductase: production of both the functional molybdenum-containing domain and the nonfunctional tungsten analog.
[So] Source:Arch Biochem Biophys;403(2):237-48, 2002 Jul 15.
[Is] ISSN:0003-9861
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Assimilatory NADH:nitrate reductase (EC 1.6.6.1), a complex molybdenum-, cytochrome b(557)- and FAD-containing protein, catalyzes the regulated and rate-limiting step in the utilization of inorganic nitrogen by higher plants. To facilitate structure/function studies of the individual molybdenum center, we have developed bacterial expression systems for the heterologous production of the 541 residue amino-terminal, molybdenum center-containing domain of spinach nitrate reductase either as a six-histidine-tagged variant or as a glutathione-S-transferase-tagged fusion protein. Expression of the his-tagged molybdenum domain in Escherichia coli BL21(DE3) cells under anaerobic conditions yielded a 55-kDa domain with a specific activity of 1.5 micromol NO(3)(-) consumed/min/nmol enzyme and with a K(mapp)(NO(3)(-)) of 8 mciroM. In contrast, expression of the molybdenum domain as a GST-tagged fusion protein in E. coli TP1000(MobA(-) strain) cells under aerobic conditions yielded an 85-kDa fusion protein with a specific activity of 10.8 micromol NO(3)(-) consumed/min/nmol enzyme and with a K(mapp)(NO(3)(-)) of 12 microM. Fluorescence analysis indicated that both forms of the molybdenum domain contained the cofactor, MPT, although the MPT content was higher in the GST-fusion domain. Inductively coupled plasma mass spectrometric analysis of both the his-tagged and GST-fusion protein domain samples indicated Mo/protein ratios of 0.44 and 0.93, respectively, confirming a very high level of Mo incorporation in the GST-fusion protein. Expression of the GST-fusion protein in TP1000 cells in the presence of elevated tungsten concentrations resulted in an 85-kDa fusion protein that contained MPT but which was devoid of nitrate-reducing activity. Partial reduction of the molybdenum domain resulted in the generation of an axial Mo(V) EPR species with g values of 1.9952, 1.9693, and 1.9665, respectively, and exhibiting superhyperfine coupling to a single exchangeable proton, analogous to that previously observed for the native enzyme. In contrast, the tungsten-substituted MPT-containing domain yielded a W(V) EPR species with g values of 1.9560, 1.9474, and 1.9271, respectively, with unresolved superhyperfine interaction. NADH:nitrate reductase activity could be reconstituted using the GST-molybdenum domain fusion protein in the presence of the recombinant forms of the spinach nitrate reductase' flavin- and heme-containing domains.
[Mh] Termos MeSH primário: Escherichia coli/genética
Molibdênio/metabolismo
Nitrato Redutases/genética
Nitrato Redutases/metabolismo
Tungstênio/metabolismo
[Mh] Termos MeSH secundário: Domínio Catalítico
Dicroísmo Circular
Espectroscopia de Ressonância de Spin Eletrônica
Vetores Genéticos
Nitrato Redutase (NAD(P)H)
Nitrato Redutases/química
Engenharia de Proteínas/métodos
Proteínas Recombinantes de Fusão/genética
Proteínas Recombinantes de Fusão/metabolismo
Spinacia oleracea/enzimologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Recombinant Fusion Proteins); 81AH48963U (Molybdenum); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H)); V9306CXO6G (Tungsten)
[Em] Mês de entrada:0208
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:020726
[St] Status:MEDLINE


  8 / 25 MEDLINE  
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[PMID]:11289301
[Au] Autor:Campbell WH
[Ad] Endereço:Department of Biological Sciences, Phytotechnology Research Center, Michigan Technological University, Houghton, Michigan 49931, USA. wcampbel@mtu.edu
[Ti] Título:Structure and function of eukaryotic NAD(P)H:nitrate reductase.
[So] Source:Cell Mol Life Sci;58(2):194-204, 2001 Feb.
[Is] ISSN:1420-682X
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Pyridine nucleotide-dependent nitrate reductases (NRs; EC 1.6.6.1-3) are molybdenum-containing enzymes found in eukaryotic organisms which assimilate nitrate. NR is a homodimer with an approximately 100 kDa polypeptide which folds into stable domains housing each of the enzyme's redox cofactors--FAD, heme-Fe molybdopterin (Mo-MPT) and the electron donor NAD(P)H--and there is also a domain for the dimer interface. NR has two active sites: the nitrate-reducing Mo-containing active site and the pyridine nucleotide active site formed between the FAD and NAD(P)H domains. The major barriers to defining the mechanism of catalysis for NR are obtaining the detailed three-dimensional structures for oxidized and reduced enzyme and more in-depth analysis of electron transfer rates in holo-NR. Recombinant expression of holo-NR and its fragments, including site-directed mutagenesis of key acative site and domain interface residues, are expected to make large contributions to this effort to understand the catalytic mechanism of NR.
[Mh] Termos MeSH primário: Nitrato Redutases/química
[Mh] Termos MeSH secundário: Domínio Catalítico
Células Eucarióticas/enzimologia
Holoenzimas/química
Holoenzimas/genética
Holoenzimas/metabolismo
Nitrato Redutase (NAD(P)H)
Nitrato Redutases/genética
Nitrato Redutases/metabolismo
Oxirredução
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.; REVIEW
[Nm] Nome de substância:
0 (Holoenzymes); 0 (Recombinant Proteins); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H))
[Em] Mês de entrada:0104
[Cu] Atualização por classe:061115
[Lr] Data última revisão:
061115
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:010406
[St] Status:MEDLINE


  9 / 25 MEDLINE  
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[PMID]:11996117
[Au] Autor:Nivinskas H; Koder RL; Anusevicius Z; Sarlauskas J; Miller AF; Cenas N
[Ad] Endereço:Institute of Biochemistry, Vilnius, Lithuania.
[Ti] Título:Two-electron reduction of nitroaromatic compounds by Enterobacter cloacae NAD(P)H nitroreductase: description of quantitative structure-activity relationships.
[So] Source:Acta Biochim Pol;47(4):941-9, 2000.
[Is] ISSN:0001-527X
[Cp] País de publicação:Poland
[La] Idioma:eng
[Ab] Resumo:Enterobacter cloacae NAD(P)H:nitroreductase catalyzes the reduction of a series of nitroaromatic compounds with steady-state bimolecular rate constants (kcat/Km) ranging from 10(4) M(-1) s(-1) to 10(7) M(-1) s(-1), and oxidizing 2 moles NADH per mole mononitrocompound. Oxidation of excess NADH by polynitrobenzenes including explosives 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenyl-N-methylnitramine (tetryl), has been observed as a slower secondary process, accompanied by O2 consumption. This type of 'redox cycling' was not related to reactions of nitroaromatic anion-radicals, but was caused by the autoxidation of relatively stable reaction products. The logs kcat/Km of all the compounds examined exhibited parabolic dependence on their enthalpies of single-electron- or two-electron (hydride) reduction, obtained by quantum mechanical calculations. This type of quantitative structure-activity relationships shows that the reactivity of nitroaromatics towards E. cloacae nitroreductase depends mainly on their hydride accepting properties, but not on their particular structure, and does not exclude the possibility of multistep hydride transfer.
[Mh] Termos MeSH primário: Enterobacter cloacae/enzimologia
Nitrato Redutases/química
Nitrato Redutases/metabolismo
[Mh] Termos MeSH secundário: Elétrons
Cinética
Modelos Químicos
Nitrato Redutase (NAD(P)H)
Oxigênio/metabolismo
Relação Estrutura-Atividade
Termodinâmica
Trinitrotolueno/farmacologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
118-96-7 (Trinitrotoluene); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H)); S88TT14065 (Oxygen)
[Em] Mês de entrada:0206
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:020509
[St] Status:MEDLINE


  10 / 25 MEDLINE  
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[PMID]:10846218
[Au] Autor:Hall N; Tomsett AB
[Ad] Endereço:School of Biological Sciences, The University of Liverpool, Donnan Laboratories, Liverpool L69 7ZD, UK.
[Ti] Título:Structure-function analysis of NADPH:nitrate reductase from Aspergillus nidulans: analysis of altered pyridine nucleotide specificity in vivo.
[So] Source:Microbiology;146 ( Pt 6):1399-406, 2000 Jun.
[Is] ISSN:1350-0872
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Nitrate reductase (NaR) catalyses the reduction of nitrate to nitrite via a two-electron transfer. In fungi, the electron donor for NaR is NADPH whereas plants can have two enzymes, NADH:NaR and a bispecific NAD(P)H:NaR. PCR mutagenesis was employed to introduce mutations into the niaD gene of Aspergillus nidulans in order to identify residues involved in co-enzyme specificity. The niaD3000 mutation (NiaD T813D, K814Q) altered co-enzyme specificity: the new enzyme had high levels of NADH:NaR activity in vitro, whilst all NADPH-associated activity was lost. However, strains carrying this mutation did not grow on nitrate. Enzyme assays suggested that this was not due to inhibition of the mutant enzyme by NADPH. All revertants of the niaD3000 mutants had restored NADPH activity and lost NADH activity. Sequence analysis of these revertants showed that they all contained a single amino acid change at Asp-813, suggesting that this position is crucial to co-enzyme specificity. Further studies have shown that the mutant enzyme was not protected from deactivation by either co-factor in cell-free extracts (unlike the wild-type), and that induction of the glucose-6-phosphate dehydrogenase occurred independently of NADPH levels. These data highlight the importance of functional tests in vivo under physiological conditions.
[Mh] Termos MeSH primário: Aspergillus nidulans/enzimologia
Nitrato Redutases/metabolismo
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Aspergillus nidulans/genética
Aspergillus nidulans/crescimento & desenvolvimento
Sequência de Bases
Coenzimas/metabolismo
DNA Fúngico/genética
Genes Fúngicos
Mutagênese Sítio-Dirigida
Mutação
NAD/metabolismo
NADP/metabolismo
Nitrato Redutase (NAD(P)H)
Nitrato Redutases/química
Nitrato Redutases/genética
Ácido Nítrico/metabolismo
Fenótipo
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Coenzymes); 0 (DNA, Fungal); 0U46U6E8UK (NAD); 411VRN1TV4 (Nitric Acid); 53-59-8 (NADP); EC 1.7.- (Nitrate Reductases); EC 1.7.1.2 (Nitrate Reductase (NAD(P)H))
[Em] Mês de entrada:0008
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:000610
[St] Status:MEDLINE



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