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  1 / 27 MEDLINE  
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[PMID]:25745028
[Au] Autor:Yoneyama T; Fujimori T; Yanagisawa S; Hase T; Suzuki A
[Ad] Endereço:Department of Applied Biological Chemistry, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657 Japan tadakatsu_yoneyama@opal.ocn.ne.jp.
[Ti] Título:15N Tracing Studies on In Vitro Reactions of Ferredoxin-Dependent Nitrite Reductase and Glutamate Synthase Using Reconstituted Electron Donation Systems.
[So] Source:Plant Cell Physiol;56(6):1154-61, 2015 Jun.
[Is] ISSN:1471-9053
[Cp] País de publicação:Japan
[La] Idioma:eng
[Ab] Resumo:It is known that plants contain ferredoxin (Fd)-dependent nitrite reductase (NiR) and glutamate synthase (GOGAT). The Fd-NiR reaction produces ammonia from nitrite, and the activity is usually measured by nitrite disappearance. The Fd-GOGAT reaction forms two glutamates of different origin, from glutamine and 2-oxoglutarate, and the activity is measured by the oxidation of reductant (NADPH) or by formation of total glutamate. Here, a quantitative probe of the products and efficiency of the process was conducted using (15)N tracing techniques on these reactions in vitro. We quantified the reduction of (15)N-labeled [Formula: see text] to [Formula: see text] and the formation of [(15)N]glutamate and [(14)N]glutamate from [5-(15)N-amide]glutamine plus 2-oxoglutarate by NiR and GOGAT, respectively, with the reductant-Fd-NADP(+) oxidoreductase (FNR)-Fd system as the sequential electron donors. The supply of dithionite or NADPH to recombinant cyanobacterial NiR led to electron donation system-dependent formation of [(15)N]ammonium from [(15)N]nitrite. Addition of 20 mM NaCl and 20 mM Na-ascorbate accelerated nitrite reduction under high concentrations of NADPH. A sufficient supply of NADPH to recombinant Zea mays Fd-GOGAT generated complete GOGAT activity (transferring the [5-(15)N]amide of glutamine to 2-oxoglutarate to form [(15)N]glutamate), whereas a shortage of NADPH resulted in glutaminase activity only, which removed the amide from glutamine and released ammonia and [(14)N]glutamate. We conclude that although the recombinant Fd-GOGAT enzyme has two forms of glutamate synthesis, the first by glutaminase (ammonia release by glutamine amidotransferase) and the second by glutamate synthase (coupling of the ammonia and exogenously applied 2-oxoglutarate), the first works without NADPH, while the second is strictly dependent on NADPH availability.
[Mh] Termos MeSH primário: Elétrons
Ferredoxina-Nitrito Redutase/metabolismo
Glutamato Sintase/metabolismo
Marcação por Isótopo
Zea mays/enzimologia
[Mh] Termos MeSH secundário: Compostos de Amônio/metabolismo
Glutamatos/biossíntese
Ácido Glutâmico/metabolismo
Glutaminase/metabolismo
NADP/metabolismo
Nitritos/metabolismo
Isótopos de Nitrogênio
Recombinação Genética/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Ammonium Compounds); 0 (Glutamates); 0 (Nitrites); 0 (Nitrogen Isotopes); 3KX376GY7L (Glutamic Acid); 53-59-8 (NADP); EC 1.4.1.13 (Glutamate Synthase); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase); EC 3.5.1.2 (Glutaminase)
[Em] Mês de entrada:1603
[Cu] Atualização por classe:150609
[Lr] Data última revisão:
150609
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150307
[St] Status:MEDLINE
[do] DOI:10.1093/pcp/pcv039


  2 / 27 MEDLINE  
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[PMID]:22843026
[Au] Autor:Wakasa Y; Ozawa K; Takaiwa F
[Ad] Endereço:Functional Transgenic Crops Research Unit, Genetically Modified Organism Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8602, Japan. ywakasa@nias.affrc.go.jp
[Ti] Título:Agrobacterium-mediated co-transformation of rice using two selectable marker genes derived from rice genome components.
[So] Source:Plant Cell Rep;31(11):2075-84, 2012 Nov.
[Is] ISSN:1432-203X
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:A method for Agrobacterium-mediated co-transformation of rice (Oryza sativa L.) was developed using rice-derived selection markers. Two T-DNAs were efficiently introduced into separate loci using selectable marker gene cassettes consisting of the mutated acetolactate synthase gene (mALS) under the control of the callus-specific promoter (CSP) (CSP:mALS) and the ferredoxin nitrite reductase gene (NiR) under the control of its own promoter (NiR P:NiR). The CSP:mALS gene cassette confers sulfonylurea herbicide resistance to transgenic rice callus. The NiR P:NiR construct complements NiR-deficient mutant cultivars such as 'Koshihikari', which are defective in the regulation of nitrogen metabolism. In the present study, the CaMV35S:GUS and CaMV35S:GFP gene cassettes were co-introduced into the 'Koshihikari' genome using our system. Approximately 5-10 independent transgenic lines expressing both the GUS and GFP reporters were obtained from 100 Agrobacterium co-inoculated calli. Furthermore, transgenic 'Koshihikari' rice lines with reduced content of two major seed allergen proteins, the 33 and 14-16 kDa allergens, were generated by this co-transformation system. The present results indicate that the generation of selectable antibiotic resistance marker gene-free transgenic rice is possible using our rice-derived selection marker co-transformation system. Key message An improved rice transformation method was developed based on Agrobacterium-mediated co-transformation using two rice genome-derived selectable marker gene cassettes.
[Mh] Termos MeSH primário: Agrobacterium/fisiologia
Oryza/genética
Proteínas de Plantas/genética
Plantas Geneticamente Modificadas
Regiões Promotoras Genéticas/genética
[Mh] Termos MeSH secundário: Acetolactato Sintase/genética
Alérgenos/genética
DNA Bacteriano
Ferredoxina-Nitrito Redutase/genética
Genes Reporter
Marcadores Genéticos
Resistência a Herbicidas
Mutação
Oryza/efeitos dos fármacos
Oryza/enzimologia
Proteínas de Plantas/metabolismo
Regeneração
Sementes/enzimologia
Sementes/genética
Compostos de Sulfonilureia/farmacologia
Transformação Genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Allergens); 0 (DNA, Bacterial); 0 (Genetic Markers); 0 (Plant Proteins); 0 (Sulfonylurea Compounds); 0 (T-DNA); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase); EC 2.2.1.6 (Acetolactate Synthase)
[Em] Mês de entrada:1303
[Cu] Atualização por classe:171004
[Lr] Data última revisão:
171004
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120731
[St] Status:MEDLINE
[do] DOI:10.1007/s00299-012-1318-9


  3 / 27 MEDLINE  
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[PMID]:20857287
[Au] Autor:Qu Y; Zhou H; Li A; Ma F; Zhou J
[Ad] Endereço:Dalian University of Technology, China.
[Ti] Título:Nitroreductase activity of ferredoxin reductase BphA4 from Dyella ginsengisoli LA-4 by catalytic and structural properties analysis.
[So] Source:Appl Microbiol Biotechnol;89(3):655-63, 2011 Feb.
[Is] ISSN:1432-0614
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Ferredoxin reductase BphA4 was well known as a component of biphenyl dioxygenase. However, there was little information about whether it could utilize nonphysiological oxidants as electron acceptors. In the present study, we reported the novel nitroreductase activity of BphA4(LA)â‚‹4. The homology model of ferredoxin reductase BphA4 from Dyella ginsengisoli LA-4 was constructed. According to the alignment of three-dimensional structures, it was supposed that BphA4(LA)â‚‹4 could function as nitroreductase. Recombinant His-tagged BphA4(LA)â‚‹4 was purified with a molecular mass of 49.6 ± 1 kDa. Biochemical characterization of purified BphA4(LA)â‚‹4 possessed the nitroreductase activity with the optimal temperature 50°C and pH 8.0. The substrate spectrum and kinetics indicated BphA4(LA)â‚‹4 could reduce several nitroaromatics with different apparent K(m) values: m-dinitrobenzene (560 µM), o-dinitrobenzene (1,060 µM), o-nitroaniline (1,570 µM), m-nitrobenzoic acid (1,300 µM) and m-nitrophenol (67 µM). The nitroreductase activity was further explained by docking studies, which was indicated that Arg 288 should play an important role in binding nitroaromatics. Moreover, there existed a good linear correlation between lnK(m) and calculated binding energy.
[Mh] Termos MeSH primário: Ferredoxina-Nitrito Redutase/genética
Ferredoxina-Nitrito Redutase/metabolismo
Xanthomonadaceae/enzimologia
[Mh] Termos MeSH secundário: Ferredoxina-Nitrito Redutase/química
Ferredoxina-Nitrito Redutase/isolamento & purificação
Concentração de Íons de Hidrogênio
Cinética
Modelos Moleculares
Peso Molecular
Estrutura Terciária de Proteína
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/isolamento & purificação
Proteínas Recombinantes/metabolismo
Homologia de Sequência de Aminoácidos
Especificidade por Substrato
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Recombinant Proteins); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase)
[Em] Mês de entrada:1104
[Cu] Atualização por classe:110120
[Lr] Data última revisão:
110120
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:100922
[St] Status:MEDLINE
[do] DOI:10.1007/s00253-010-2874-y


  4 / 27 MEDLINE  
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[PMID]:20550143
[Au] Autor:Alberty RA
[Ad] Endereço:Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. alberty@mit.edu
[Ti] Título:Consumption of hydrogen ions in rapid-equilibrium enzyme kinetics.
[So] Source:J Phys Chem B;114(49):16083-6, 2010 Dec 16.
[Is] ISSN:1520-5207
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Enzyme-catalyzed reductase reactions in particular are characterized by large changes in the binding of hydrogen ions Δ(r)N(H). This is a thermodynamic property of the reaction that is catalyzed. For example, in the ferredoxin-nitrite reductase reaction, there is an increase of eight in the binding of hydrogen ions for every molecule of nitrite reduced to ammonia H(2)O. If these hydrogen ions are consumed in the rate-determining reaction, the limiting velocity is proportional to [H(+)](8). This would make it practically impossible to determine the kinetic parameters. This article shows that when n hydrogen ions are consumed in reactions preceding the rate-determining reaction the limiting velocity is not proportional to [H(+)](n) and may only vary with pH according to the pK's of the enzyme-substrate complex that produces products. Rapid-equilibrium rate equations for ordered A + B → products are derived for two mechanisms in which a single hydrogen ion is consumed prior to the rate-determining reaction. Rate equations are tested by calculating velocities for the minimum number of velocity measurements required to estimate the kinetic parameters and using these velocities to estimate the kinetic parameters.
[Mh] Termos MeSH primário: Termodinâmica
[Mh] Termos MeSH secundário: Catálise
Ferredoxina-Nitrito Redutase/química
Concentração de Íons de Hidrogênio
Cinética
Prótons
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Protons); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase)
[Em] Mês de entrada:1104
[Cu] Atualização por classe:101214
[Lr] Data última revisão:
101214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:100617
[St] Status:MEDLINE
[do] DOI:10.1021/jp911945q


  5 / 27 MEDLINE  
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[PMID]:20494107
[Au] Autor:Schnell R; Schneider G
[Ad] Endereço:Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden.
[Ti] Título:Structural enzymology of sulphur metabolism in Mycobacterium tuberculosis.
[So] Source:Biochem Biophys Res Commun;396(1):33-8, 2010 May 21.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The emergence of multidrug-resistant strains of Mycobacterium tuberculosis poses a serious threat to human health and has led to world-wide efforts focusing on the development of novel vaccines and antibiotics against this pathogen. Sulphur metabolism in this organism has been linked to essential processes such as virulence and redox defence. The cysteine biosynthetic pathway is up-regulated in models of persistent M. tuberculosis infections and provides potential targets for novel anti-mycobacterial agents, directed specifically toward the pathogen in its persistent phase. Functional and structural characterization of enzymes from sulfur metabolism establishes a necessary framework for the design of strong binding inhibitors that might be developed into new drugs. This review summarizes recent progress in the elucidation of the structural enzymology of the sulphate reduction and cysteine biosynthesis pathways.
[Mh] Termos MeSH primário: Cisteína Sintase/metabolismo
Cisteína/biossíntese
Ferredoxina-Nitrito Redutase/metabolismo
Mycobacterium tuberculosis/enzimologia
Serina O-Acetiltransferase/metabolismo
Enxofre/metabolismo
[Mh] Termos MeSH secundário: Ferredoxina-Nitrito Redutase/química
Conformação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; REVIEW
[Nm] Nome de substância:
70FD1KFU70 (Sulfur); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase); EC 2.3.1.30 (Serine O-Acetyltransferase); EC 2.5.1.47 (Cysteine Synthase); K848JZ4886 (Cysteine)
[Em] Mês de entrada:1006
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:100525
[St] Status:MEDLINE
[do] DOI:10.1016/j.bbrc.2010.02.118


  6 / 27 MEDLINE  
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[PMID]:20039132
[Au] Autor:Hirasawa M; Tripathy JN; Sommer F; Somasundaram R; Chung JS; Nestander M; Kruthiventi M; Zabet-Moghaddam M; Johnson MK; Merchant SS; Allen JP; Knaff DB
[Ad] Endereço:Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, 79409-1061, USA.
[Ti] Título:Enzymatic properties of the ferredoxin-dependent nitrite reductase from Chlamydomonas reinhardtii. Evidence for hydroxylamine as a late intermediate in ammonia production.
[So] Source:Photosynth Res;103(2):67-77, 2010 Feb.
[Is] ISSN:1573-5079
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo: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 that the structure of C. reinhardtii nitrite reductase will be similar to that of the spinach enzyme. Chemical modification studies and the ionic-strength dependence of the enzyme's ability to interact with ferredoxin are consistent with the involvement of arginine and lysine residues on C. reinhardtii nitrite reductase in electrostatically-stabilized binding to ferredoxin. The C. reinhardtii enzyme has been used to demonstrate that hydroxylamine can serve as an electron-accepting substrate for the enzyme and that the product of hydroxylamine reduction is ammonia, providing the first experimental evidence for the hypothesis that hydroxylamine, bound to the enzyme, can serve as a late intermediate during the reduction of nitrite to ammonia catalyzed by the enzyme.
[Mh] Termos MeSH primário: Amônia/metabolismo
Chlamydomonas reinhardtii/enzimologia
Ferredoxina-Nitrito Redutase/metabolismo
Hidroxilamina/metabolismo
[Mh] Termos MeSH secundário: Biocatálise
Espectroscopia de Ressonância de Spin Eletrônica
Ferredoxina-Nitrito Redutase/química
Ferredoxinas/metabolismo
Modelos Moleculares
Nitritos/metabolismo
Concentração Osmolar
Oxirredução
Estrutura Secundária de Proteína
Proteínas Recombinantes/metabolismo
Spinacia oleracea/enzimologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Ferredoxins); 0 (Nitrites); 0 (Recombinant Proteins); 2FP81O2L9Z (Hydroxylamine); 7664-41-7 (Ammonia); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase)
[Em] Mês de entrada:1109
[Cu] Atualização por classe:161122
[Lr] Data última revisão:
161122
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:091230
[St] Status:MEDLINE
[do] DOI:10.1007/s11120-009-9512-5


  7 / 27 MEDLINE  
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[PMID]:19825625
[Au] Autor:Hirasawa M; Tripathy JN; Somasundaram R; Johnson MK; Bhalla M; Allen JP; Knaff DB
[Ad] Endereço:Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA.
[Ti] Título:The interaction of spinach nitrite reductase with ferredoxin: a site-directed mutation study.
[So] Source:Mol Plant;2(3):407-15, 2009 May.
[Is] ISSN:1674-2052
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:A series of site-directed mutants of the ferredoxin-dependent spinach nitrite reductase has been characterized and several amino acids have been identified that appear to be involved in the interaction of the enzyme with ferredoxin. In a complementary study, binding constants to nitrite reductase and steady-state kinetic parameters of site-directed mutants of ferredoxin were determined in an attempt to identify ferredoxin amino acids involved in the interaction with nitrite reductase. The results have been interpreted in terms of an in-silico docking model for the 1:1 complex of ferredoxin with nitrite reductase.
[Mh] Termos MeSH primário: Sequência Conservada/genética
Ferredoxina-Nitrito Redutase/genética
Ferredoxinas/metabolismo
Mutagênese Sítio-Dirigida
Nitrito Redutases/metabolismo
[Mh] Termos MeSH secundário: Sítios de Ligação
Ferredoxina-Nitrito Redutase/metabolismo
Ferredoxinas/genética
Mutação
Nitrito Redutases/genética
Alinhamento de Sequência
Homologia de Sequência de Aminoácidos
Spinacia oleracea/enzimologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Ferredoxins); EC 1.7.- (Nitrite Reductases); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase)
[Em] Mês de entrada:1004
[Cu] Atualização por classe:161122
[Lr] Data última revisão:
161122
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:091015
[St] Status:MEDLINE
[do] DOI:10.1093/mp/ssn098


  8 / 27 MEDLINE  
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[PMID]:18319262
[Au] Autor:Trapasso F; Pichiorri F; Gaspari M; Palumbo T; Aqeilan RI; Gaudio E; Okumura H; Iuliano R; Di Leva G; Fabbri M; Birk DE; Raso C; Green-Church K; Spagnoli LG; Venuta S; Huebner K; Croce CM
[Ad] Endereço:Ohio State University, Comprehensive Cancer Center, Columbus, Ohio 43210, USA.
[Ti] Título:Fhit interaction with ferredoxin reductase triggers generation of reactive oxygen species and apoptosis of cancer cells.
[So] Source:J Biol Chem;283(20):13736-44, 2008 May 16.
[Is] ISSN:0021-9258
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Fhit protein is lost in most cancers, its restoration suppresses tumorigenicity, and virus-mediated FHIT gene therapy induces apoptosis and suppresses tumors in preclinical models. We have used protein cross-linking and proteomics methods to characterize a Fhit protein complex involved in triggering Fhit-mediated apoptosis. The complex includes Hsp60 and Hsp10 that mediate Fhit stability and may affect import into mitochondria, where it interacts with ferredoxin reductase, responsible for transferring electrons from NADPH to cytochrome P450 via ferredoxin. Viral-mediated Fhit restoration increases production of intracellular reactive oxygen species, followed by increased apoptosis of lung cancer cells under oxidative stress conditions; conversely, Fhit-negative cells escape apoptosis, carrying serious oxidative DNA damage that may contribute to an increased mutation rate. Characterization of Fhit interacting proteins has identified direct effectors of the Fhit-mediated apoptotic pathway that is lost in most cancers through loss of Fhit.
[Mh] Termos MeSH primário: Hidrolases Anidrido Ácido/metabolismo
Apoptose
Ferredoxina-Nitrito Redutase/química
Proteínas de Neoplasias/metabolismo
Neoplasias/metabolismo
[Mh] Termos MeSH secundário: Linhagem Celular Tumoral
Chaperonina 10/química
Chaperonina 60/química
Citosol/metabolismo
Dano ao DNA
Seres Humanos
Mitocôndrias/metabolismo
Modelos Biológicos
Mutação
Ligação Proteica
Espécies Reativas de Oxigênio
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T; RETRACTED PUBLICATION
[Nm] Nome de substância:
0 (Chaperonin 10); 0 (Chaperonin 60); 0 (Neoplasm Proteins); 0 (Reactive Oxygen Species); 0 (fragile histidine triad protein); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase); EC 3.6.- (Acid Anhydride Hydrolases)
[Em] Mês de entrada:0807
[Cu] Atualização por classe:170826
[Lr] Data última revisão:
170826
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:080306
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M709062200


  9 / 27 MEDLINE  
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[PMID]:17928131
[Au] Autor:Alberty RA
[Ad] Endereço:Department of Chemistry, Masssachusetts Institute of Technology, Cambridge, MA 02139, USA. alberty@mit.edu
[Ti] Título:Three mechanisms and rapid-equilibrium rate equations for a type of reductase reaction.
[So] Source:Biophys Chem;131(1-3):71-9, 2007 Dec.
[Is] ISSN:0301-4622
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Rapid-equilibrium rate equations for enzyme-catalyzed reactions are especially useful when the mechanism involves a number of pKs, but they are also useful when some reactants have stoichiometric numbers greater than one or hydrogen ions are produced or consumed in the rate-determining step. The pH dependencies of limiting velocities, Michaelis constants, and reaction velocities for the forward reaction are discussed for two examples of reductase reactions of the type mR + O -> products, where R is the reductant and O is the oxidant. For the nitrate reductase reaction (EC 1.9.6.1), m = 2 and two hydrogen ions are consumed. For the nitrite-ferredoxin reductase reaction (EC 1.7.7.1), m = 6 and eight hydrogen ions are consumed. The expressions for the limiting velocities, Michaelis constants, and rate equations for the forward reaction are derived for two ordered mechanisms and the random mechanism. Three Mathematica programs are used to make plots of kinetic parameters as functions of pH and three-dimensional plots of rapid-equilibrium velocities as functions of [O] and [R] for arbitrary sets of input parameters.
[Mh] Termos MeSH primário: Ferredoxina-Nitrito Redutase/química
Computação Matemática
Nitrato Redutase/química
[Mh] Termos MeSH secundário: Animais
Catálise
Seres Humanos
Cinética
Modelos Químicos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
EC 1.7.7.1 (Ferredoxin-Nitrite Reductase); EC 1.7.99.4 (Nitrate Reductase)
[Em] Mês de entrada:0801
[Cu] Atualização por classe:071109
[Lr] Data última revisão:
071109
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:071012
[St] Status:MEDLINE


  10 / 27 MEDLINE  
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[PMID]:16933133
[Au] Autor:Keenan BG; Wood TK
[Ad] Endereço:Artie McFerrin Department of Chemical Engineering, Texas A and M University, College Station, TX 77843-3122, USA.
[Ti] Título:Orthric Rieske dioxygenases for degrading mixtures of 2,4-dinitrotoluene/naphthalene and 2-amino-4,6-dinitrotoluene/4-amino-2,6-dinitrotoluene.
[So] Source:Appl Microbiol Biotechnol;73(4):827-38, 2006 Dec.
[Is] ISSN:0175-7598
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Pollutants are frequently found as mixtures yet it is difficult to engineer enzymes with broad substrate ranges on aromatics. Inspired by the archetypal nitroarene dioxygenase, which shares its electron transport with a salicylate monooxygenase, we have created an innovative and general approach to expand the substrate range of dioxygenase enzymes in a single cell. We have developed here a series of novel, hybrid dioxygenase enzymes that function with a single ferredoxin reductase and ferredoxin that are used to transport two electrons from nicotinamide adenine dinucleotide to the two independent terminal oxygenases. Each independent alpha-oxygenase may then be used simultaneously to create orthric enzymes that degrade mixtures of environmental pollutants. Specifically, we created a hybrid dioxygenase system consisting of naphthalene dioxygenase/dinitrotoluene dioxygenase to simultaneously degrade 2,4-dinitrotoluene and naphthalene (neither enzyme alone had significant activity on both compounds) and dinitrotoluene dioxygenase/nitrobenzene dioxygenase to simultaneously degrade the frequently encountered 2,4,6-trinitrotoluene reduction products 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene.
[Mh] Termos MeSH primário: Compostos de Anilina/metabolismo
Dinitrobenzenos/metabolismo
Dioxigenases/metabolismo
Naftalenos/metabolismo
[Mh] Termos MeSH secundário: Dioxigenases/genética
Escherichia coli/genética
Escherichia coli/metabolismo
Ferredoxina-Nitrito Redutase/genética
Ferredoxina-Nitrito Redutase/metabolismo
Ferredoxinas/genética
Ferredoxinas/metabolismo
Complexos Multienzimáticos/genética
Complexos Multienzimáticos/metabolismo
NAD/metabolismo
Oxigenases/genética
Oxigenases/metabolismo
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Aniline Compounds); 0 (Dinitrobenzenes); 0 (Ferredoxins); 0 (Multienzyme Complexes); 0 (Naphthalenes); 0 (Recombinant Proteins); 0U46U6E8UK (NAD); 189OOM840S (2-amino-4,6-dinitrotoluene); 19406-51-0 (4-amino-2,6-dinitrotoluene); 2166IN72UN (naphthalene); 6741D310ED (2,4-dinitrotoluene); EC 1.13.- (Oxygenases); EC 1.13.11.- (Dioxygenases); EC 1.14.12.- (2,4-dinitrotoluene dioxygenase); EC 1.14.12.- (naphthalene dioxygenase); EC 1.7.7.1 (Ferredoxin-Nitrite Reductase)
[Em] Mês de entrada:0704
[Cu] Atualização por classe:151119
[Lr] Data última revisão:
151119
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:060826
[St] Status:MEDLINE



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