Base de dados : MEDLINE
Pesquisa : D02.455.426.559.389.657.239.493 [Categoria DeCS]
Referências encontradas : 144 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 15 ir para página                         

  1 / 144 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29311465
[Au] Autor:Taniguchi A
[Ad] Endereço:Graduate School of Pharmaceutical Sciences, The University of Tokyo.
[Ti] Título:[Amyloid-selective Photooxygenation toward Treatment for Amyloid Diseases].
[So] Source:Yakugaku Zasshi;138(1):47-53, 2018.
[Is] ISSN:1347-5231
[Cp] País de publicação:Japan
[La] Idioma:jpn
[Ab] Resumo:Amyloid proteins and peptides form aggregates which lead to amyloid diseases. For example, Alzheimer's disease-related amyloid ß (Aß) forms oligomers, protofibrils, and amyloid fibrils, which exhibit neurotoxicity. Controlling the aggregation and toxicity of Aß would be a therapeutic strategy for the treatment of Alzheimer's disease. Recently, we have investigated an artificial oxygenative modification (chemical introduction of oxygen atoms) of amyloid proteins using a photocatalyst, which attenuated the aggregation potency and toxicity of these proteins. The oxygenation of Aß1-42 was efficiently induced using a riboflavin catalyst (1). The oxygenated Aß was less aggregative and cytotoxic than native Aß. The oxygenated Aß also showed inhibitory activity against aggregation and the onset of toxicity of native Aß. Flavin catalyst 2, bearing an Aß-binding peptide, allowed the selective oxygenation of Aß even in the presence of living cells, due to its Aß-affinity. Furthermore, "On/Off" switchable photooxygenation catalysts 3 and 4, which can sense a higher-order amyloid structure (i.e., cross-ß-sheet structure), were developed based on the amyloid fluorescence probe thioflavin-T. The photo-excited catalysts generated singlet oxygens to induce oxygenation when binding to the amyloid structure ("On"). In contrast, the free catalysts, without binding to the amyloid structure, produced no singlet oxygen, even if photo-excited ("Off"). This "On/Off" switchable function enabled highly Aß-selective oxygenation. Catalyst 3 was successfully used for the selective oxygenation of other amyloid proteins and peptides. These findings suggest that amyloid-selective oxygenation could provide a versatile system in developing effective new treatments for amyloid diseases.
[Mh] Termos MeSH primário: Doença de Alzheimer/tratamento farmacológico
Peptídeos beta-Amiloides/metabolismo
Dinitrocresóis
Agregação Patológica de Proteínas/prevenção & controle
Riboflavina
Tiazóis
[Mh] Termos MeSH secundário: Doença de Alzheimer/metabolismo
Peptídeos beta-Amiloides/química
Peptídeos beta-Amiloides/toxicidade
Catálise
Descoberta de Drogas
Seres Humanos
Oxirredução
Processos Fotoquímicos
Ligação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Amyloid beta-Peptides); 0 (Dinitrocresols); 0 (Thiazoles); 1604ZJR09T (4,6-dinitro-o-cresol); 2390-54-7 (thioflavin T); TLM2976OFR (Riboflavin)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180110
[St] Status:MEDLINE
[do] DOI:10.1248/yakushi.17-00186-2


  2 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28859089
[Au] Autor:Gujar MR; Stricker AM; Lundquist EA
[Ad] Endereço:Department of Molecular Biosciences, Program in Molecular, Cellular, and Developmental Biology, The University of Kansas, Lawrence, KS, United States of America.
[Ti] Título:Flavin monooxygenases regulate Caenorhabditis elegans axon guidance and growth cone protrusion with UNC-6/Netrin signaling and Rac GTPases.
[So] Source:PLoS Genet;13(8):e1006998, 2017 Aug.
[Is] ISSN:1553-7404
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The guidance cue UNC-6/Netrin regulates both attractive and repulsive axon guidance. Our previous work showed that in C. elegans, the attractive UNC-6/Netrin receptor UNC-40/DCC stimulates growth cone protrusion, and that the repulsive receptor, an UNC-5:UNC-40 heterodimer, inhibits growth cone protrusion. We have also shown that inhibition of growth cone protrusion downstream of the UNC-5:UNC-40 repulsive receptor involves Rac GTPases, the Rac GTP exchange factor UNC-73/Trio, and the cytoskeletal regulator UNC-33/CRMP, which mediates Semaphorin-induced growth cone collapse in other systems. The multidomain flavoprotein monooxygenase (FMO) MICAL (Molecule Interacting with CasL) also mediates growth cone collapse in response to Semaphorin by directly oxidizing F-actin, resulting in depolymerization. The C. elegans genome does not encode a multidomain MICAL-like molecule, but does encode five flavin monooxygenases (FMO-1, -2, -3, -4, and 5) and another molecule, EHBP-1, similar to the non-FMO portion of MICAL. Here we show that FMO-1, FMO-4, FMO-5, and EHBP-1 may play a role in UNC-6/Netrin directed repulsive guidance mediated through UNC-40 and UNC-5 receptors. Mutations in fmo-1, fmo-4, fmo-5, and ehbp-1 showed VD/DD axon guidance and branching defects, and variably enhanced unc-40 and unc-5 VD/DD axon guidance defects. Developing growth cones in vivo of fmo-1, fmo-4, fmo-5, and ehbp-1 mutants displayed excessive filopodial protrusion, and transgenic expression of FMO-5 inhibited growth cone protrusion. Mutations suppressed growth cone inhibition caused by activated UNC-40 and UNC-5 signaling, and activated Rac GTPase CED-10 and MIG-2, suggesting that these molecules are required downstream of UNC-6/Netrin receptors and Rac GTPases. From these studies we conclude that FMO-1, FMO-4, FMO-5, and EHBP-1 represent new players downstream of UNC-6/Netrin receptors and Rac GTPases that inhibit growth cone filopodial protrusion in repulsive axon guidance.
[Mh] Termos MeSH primário: Orientação de Axônios/genética
Proteínas de Caenorhabditis elegans/genética
Caenorhabditis elegans/genética
Oxigenases de Função Mista/genética
Proteínas do Tecido Nervoso/genética
[Mh] Termos MeSH secundário: Animais
Animais Geneticamente Modificados
Caenorhabditis elegans/crescimento & desenvolvimento
Dinitrocresóis/metabolismo
Mutação
Netrinas
Pseudópodes/genética
Pseudópodes/metabolismo
Transdução de Sinais
Proteínas rac de Ligação ao GTP/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Caenorhabditis elegans Proteins); 0 (Dinitrocresols); 0 (Nerve Tissue Proteins); 0 (Netrins); 0 (UNC-6 protein, C elegans); 1604ZJR09T (4,6-dinitro-o-cresol); EC 1.- (Mixed Function Oxygenases); EC 3.6.5.2 (rac GTP-Binding Proteins)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170901
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pgen.1006998


  3 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28661684
[Au] Autor:Adak S; Begley TP
[Ad] Endereço:Department of Chemistry, Texas A&M University , 3255 TAMU, College Station, Texas 77843, United States.
[Ti] Título:RutA-Catalyzed Oxidative Cleavage of the Uracil Amide Involves Formation of a Flavin-N5-oxide.
[So] Source:Biochemistry;56(29):3708-3709, 2017 Jul 25.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:RutA is a novel flavoenzyme on the uracil catabolic pathway that catalyzes uracil ring opening by a unique amide oxidation reaction. Here we provide evidence that this reaction also involves the formation of a flavin-N5-oxide.
[Mh] Termos MeSH primário: Dinitrocresóis/química
Modelos Químicos
Uracila/química
[Mh] Termos MeSH secundário: Catálise
Polienos/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Dinitrocresols); 0 (Polyenes); 1604ZJR09T (4,6-dinitro-o-cresol); 56HH86ZVCT (Uracil); 68248-02-2 (flavopentin)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170727
[Lr] Data última revisão:
170727
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170630
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.7b00493


  4 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28652025
[Au] Autor:Sobrado P; Tanner JJ
[Ad] Endereço:Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA. Electronic address: psobrado@vt.edu.
[Ti] Título:Multiple functionalities of reduced flavin in the non-redox reaction catalyzed by UDP-galactopyranose mutase.
[So] Source:Arch Biochem Biophys;632:59-65, 2017 Oct 15.
[Is] ISSN:1096-0384
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Flavin cofactors are widely used by enzymes to catalyze a broad range of chemical reactions. Traditionally, flavins in enzymes are regarded as redox centers, which enable enzymes to catalyze the oxidation or reduction of substrates. However, a new class of flavoenzyme has emerged over the past quarter century in which the flavin functions as a catalytic center in a non-redox reaction. Here we introduce the unifying concept of flavin hot spots to understand and categorize the mechanisms and reactivities of both traditional and noncanonical flavoenzymes. The major hot spots of reactivity include the N5, C4a, and C4O atoms of the isoalloxazine, and the 2' hydroxyl of the ribityl chain. The role of hot spots in traditional flavoenzymes, such as monooxygenases, is briefly reviewed. A more detailed description of flavin hot spots in noncanonical flavoenzymes is provided, with a focus on UDP-galactopyranose mutase, where the N5 functions as a nucleophile that attacks the anomeric carbon atom of the substrate. Recent results from mechanistic enzymology, kinetic crystallography, and computational chemistry provide a complete picture of the chemical mechanism of UDP-galactopyranose mutase.
[Mh] Termos MeSH primário: Dinitrocresóis/química
Flavoproteínas/química
Transferases Intramoleculares/química
[Mh] Termos MeSH secundário: Catálise
Dinitrocresóis/metabolismo
Flavoproteínas/metabolismo
Transferases Intramoleculares/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Dinitrocresols); 0 (Flavoproteins); 1604ZJR09T (4,6-dinitro-o-cresol); EC 5.4.- (Intramolecular Transferases)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171026
[Lr] Data última revisão:
171026
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170628
[St] Status:MEDLINE


  5 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28515321
[Au] Autor:Rossner R; Kaeberlein M; Leiser SF
[Ad] Endereço:From the Department of Pathology, University of Washington, Seattle, Washington 98195 and.
[Ti] Título:Flavin-containing monooxygenases in aging and disease: Emerging roles for ancient enzymes.
[So] Source:J Biol Chem;292(27):11138-11146, 2017 Jul 07.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Flavin-containing monooxygenases (FMOs) are primarily studied as xenobiotic metabolizing enzymes with a prominent role in drug metabolism. In contrast, endogenous functions and substrates of FMOs are less well understood. A growing body of recent evidence, however, implicates FMOs in aging, several diseases, and metabolic pathways. The evidence suggests an important role for these well-conserved proteins in multiple processes and raises questions about the endogenous substrate(s) and regulation of FMOs. Here, we present an overview of evidence for FMOs' involvement in aging and disease, discussing the biological context and arguing for increased investigation into the function of these enzymes.
[Mh] Termos MeSH primário: Dinitrocresóis/metabolismo
Evolução Molecular
Oxigenases de Função Mista/genética
Oxigenases de Função Mista/metabolismo
[Mh] Termos MeSH secundário: Animais
Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Dinitrocresols); 1604ZJR09T (4,6-dinitro-o-cresol); EC 1.- (Mixed Function Oxygenases)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170714
[Lr] Data última revisão:
170714
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170519
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.R117.779678


  6 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
[PMID]:27933790
[Au] Autor:Tararina MA; Janda KD; Allen KN
[Ad] Endereço:Program in Biomolecular Pharmacology, Boston University School of Medicine , 72 East Concord Street, Boston, Massachusetts 02118, United States.
[Ti] Título:Structural Analysis Provides Mechanistic Insight into Nicotine Oxidoreductase from Pseudomonas putida.
[So] Source:Biochemistry;55(48):6595-6598, 2016 Dec 06.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The first structure of nicotine oxidoreductase (NicA2) was determined by X-ray crystallography. Pseudomonas putida has evolved nicotine-degrading activity to provide a source of carbon and nitrogen. The structure establishes NicA2 as a member of the monoamine oxidase family. Residues 1-50 are disordered and may play a role in localization. The nicotine-binding site proximal to the isoalloxazine ring of flavin shows an unusual composition of the classical aromatic cage (W427 and N462). The active site architecture is consistent with the proposed binding of the deprotonated form of the substrate and the flavin-dependent oxidation of the pyrrolidone C-N bond followed by nonenzymatic hydrolysis.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Nicotina/metabolismo
Oxirredutases/metabolismo
Pseudomonas putida/enzimologia
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Proteínas de Bactérias/química
Sítios de Ligação/genética
Domínio Catalítico
Cristalografia por Raios X
Dinitrocresóis/química
Dinitrocresóis/metabolismo
Flavinas/química
Flavinas/metabolismo
Modelos Químicos
Modelos Moleculares
Estrutura Molecular
Monoaminoxidase/química
Monoaminoxidase/genética
Monoaminoxidase/metabolismo
Nicotina/química
Oxirredução
Oxirredutases/química
Oxirredutases/genética
Domínios Proteicos
Estrutura Secundária de Proteína
Pseudomonas putida/genética
Pseudomonas putida/metabolismo
Homologia de Sequência de Aminoácidos
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Dinitrocresols); 0 (Flavins); 1604ZJR09T (4,6-dinitro-o-cresol); 490-59-5 (isoalloxazine); 6M3C89ZY6R (Nicotine); EC 1.- (Oxidoreductases); EC 1.4.3.4 (Monoamine Oxidase)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170529
[Lr] Data última revisão:
170529
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161210
[St] Status:MEDLINE


  7 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
[PMID]:27738168
[Au] Autor:Zhang M; Wang L; Shu S; Sancar A; Zhong D
[Ad] Endereço:Department of Physics, Department of Chemistry and Biochemistry, and Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
[Ti] Título:Bifurcating electron-transfer pathways in DNA photolyases determine the repair quantum yield.
[So] Source:Science;354(6309):209-213, 2016 10 14.
[Is] ISSN:1095-9203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Photolyase is a blue-light-activated enzyme that repairs ultraviolet-induced DNA damage that occurs in the form of cyclobutane pyrimidine dimers (CPDs) and pyrimidine-pyrimidone (6-4) photoproducts. Previous studies on microbial photolyases have revealed an electron-tunneling pathway that is critical for the repair mechanism. In this study, we used femtosecond spectroscopy to deconvolute seven electron-transfer reactions in 10 elementary steps in all classes of CPD photolyases. We report a unified electron-transfer pathway through a conserved structural configuration that bifurcates to favor direct tunneling in prokaryotes and a two-step hopping mechanism in eukaryotes. Both bifurcation routes are operative, but their relative contributions, dictated by the reduction potentials of the flavin cofactor and the substrate, determine the overall quantum yield of repair.
[Mh] Termos MeSH primário: Dano ao DNA
Reparo do DNA
DNA/química
Desoxirribodipirimidina Fotoliase/química
Transporte de Elétrons
Dímeros de Pirimidina/química
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Coenzimas/química
Desoxirribodipirimidina Fotoliase/classificação
Dinitrocresóis/química
Elétrons
Células Eucarióticas/enzimologia
Filogenia
Conformação Proteica
Teoria Quântica
Análise Espectral/métodos
Especificidade por Substrato
Raios Ultravioleta
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Coenzymes); 0 (Dinitrocresols); 0 (Pyrimidine Dimers); 1604ZJR09T (4,6-dinitro-o-cresol); 9007-49-2 (DNA); EC 4.1.99.3 (Deoxyribodipyrimidine Photo-Lyase)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170915
[Lr] Data última revisão:
170915
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161015
[St] Status:MEDLINE


  8 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27490826
[Au] Autor:Sa N; Rawat R; Thornburg C; Walker KD; Roje S
[Ad] Endereço:Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA.
[Ti] Título:Identification and characterization of the missing phosphatase on the riboflavin biosynthesis pathway in Arabidopsis thaliana.
[So] Source:Plant J;88(5):705-716, 2016 Dec.
[Is] ISSN:1365-313X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Despite the importance of riboflavin as the direct precursor of the cofactors flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), the physiologically relevant catalyst dephosphorylating the riboflavin biosynthesis pathway intermediate 5-amino-6-ribitylamino-2,4(1H,3H) pyrimidinedione 5'-phosphate (ARPP) has not been characterized from any organism. By using as the query sequence a previously identified plastidial FMN hydrolase AtcpFHy1 (At1g79790), belonging to the haloacid dehalogenase (HAD) superfamily, seven candidates for the missing ARPP phosphatase were found, cloned, recombinantly expressed, and purified. Activity screening showed that the enzymes encoded by AtcpFHy1, At4g11570, and At4g25840 catalyze dephosphorylation of ARPP. AtcpFHy1 was renamed AtcpFHy/PyrP1, At4g11570 and At4g25840 were named AtPyrP2 and AtGpp1/PyrP3, respectively. Subcellular localization in planta indicated that AtPyrP2 was localized in plastids and AtGpp1/PyrP3 in mitochondria. Biochemical characterization of AtcpFHy/PyrP1 and AtPyrP2 showed that they have similar K values for the substrate ARPP, with AtcpFHy/PyrP1 having higher catalytic efficiency. Screening of 21 phosphorylated substrates showed that AtPyrP2 is specific for ARPP. Molecular weights of AtcpFHy/PyrP1 and AtPyrP2 were estimated at 46 and 72 kDa, suggesting dimers. pH and temperature optima for AtcpFHy/PyrP1 and AtPyrP2 were ~7.0-8.5 and 40-50°C. T-DNA knockout of AtcpFHy/PyrP1 did not affect the flavin profile of the transgenic plants, whereas silencing of AtPyrP2 decreased accumulation of riboflavin, FMN, and FAD. Our results strongly support AtPyrP2 as the missing phosphatase on the riboflavin biosynthesis pathway in Arabidopsis thaliana. The identification of this enzyme closes a long-standing gap in understanding of the riboflavin biosynthesis in plants.
[Mh] Termos MeSH primário: Arabidopsis/enzimologia
Arabidopsis/metabolismo
Hidrolases/metabolismo
Riboflavina/biossíntese
[Mh] Termos MeSH secundário: Dinitrocresóis/metabolismo
Mononucleotídeo de Flavina/metabolismo
Flavina-Adenina Dinucleotídeo/metabolismo
Nucleotídeos de Uracila/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (5-amino-6-ribitylamino-2,4(1H,3H)pyrimidinedione 5'-phosphate); 0 (Dinitrocresols); 0 (Uracil Nucleotides); 146-14-5 (Flavin-Adenine Dinucleotide); 1604ZJR09T (4,6-dinitro-o-cresol); 7N464URE7E (Flavin Mononucleotide); EC 3.- (Hydrolases); EC 3.8.1.2 (2-haloacid dehalogenase); TLM2976OFR (Riboflavin)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171107
[Lr] Data última revisão:
171107
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160805
[St] Status:MEDLINE
[do] DOI:10.1111/tpj.13291


  9 / 144 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27307041
[Au] Autor:Machovina MM; Usselman RJ; DuBois JL
[Ad] Endereço:From the Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715-3400.
[Ti] Título:Monooxygenase Substrates Mimic Flavin to Catalyze Cofactorless Oxygenations.
[So] Source:J Biol Chem;291(34):17816-28, 2016 08 19.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Members of the antibiotic biosynthesis monooxygenase family catalyze O2-dependent oxidations and oxygenations in the absence of any metallo- or organic cofactor. How these enzymes surmount the kinetic barrier to reactions between singlet substrates and triplet O2 is unclear, but the reactions have been proposed to occur via a flavin-like mechanism, where the substrate acts in lieu of a flavin cofactor. To test this model, we monitored the uncatalyzed and enzymatic reactions of dithranol, a substrate for the nogalamycin monooxygenase (NMO) from Streptomyces nogalater As with flavin, dithranol oxidation was faster at a higher pH, although the reaction did not appear to be base-catalyzed. Rather, conserved asparagines contributed to suppression of the substrate pKa The same residues were critical for enzymatic catalysis that, consistent with the flavoenzyme model, occurred via an O2-dependent slow step. Evidence for a superoxide/substrate radical pair intermediate came from detection of enzyme-bound superoxide during turnover. Small molecule and enzymatic superoxide traps suppressed formation of the oxygenation product under uncatalyzed conditions, whereas only the small molecule trap had an effect in the presence of NMO. This suggested that NMO both accelerated the formation and directed the recombination of a superoxide/dithranyl radical pair. These catalytic strategies are in some ways flavin-like and stand in contrast to the mechanisms of urate oxidase and (1H)-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase, both cofactor-independent enzymes that surmount the barriers to direct substrate/O2 reactivity via markedly different means.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Dinitrocresóis/química
Oxigenases de Função Mista/química
Streptomyces/enzimologia
Superóxidos/química
[Mh] Termos MeSH secundário: Catálise
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Dinitrocresols); 11062-77-4 (Superoxides); 1604ZJR09T (4,6-dinitro-o-cresol); EC 1.- (Mixed Function Oxygenases)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:171120
[Lr] Data última revisão:
171120
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160617
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M116.730051


  10 / 144 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27243445
[Au] Autor:Tanvir S; Thuróczy G; Selmaoui B; Silva Pires Antonietti V; Sonnet P; Arnaud-Cormos D; Lévêque P; Pulvin S; de Seze R
[Ad] Endereço:Sorbonne Universités, Université de Technologie de Compiègne, Laboratoire de Génie Enzymatique et Cellulaire, FRE CNRS 3580, CS60319, 60203 Compiègne Cedex. France.
[Ti] Título:Effects of 3G cell phone exposure on the structure and function of the human cytochrome P450 reductase.
[So] Source:Bioelectrochemistry;111:62-9, 2016 Oct.
[Is] ISSN:1878-562X
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Cell phones increase exposure to radiofrequency (RF) electromagnetic fields (EMFs). Whether EMFs exert specific effects on biological systems remains debatable. This study investigated the effect of cell phone exposure on the structure and function of human NADPH-cytochrome P450 reductase (CPR). CPR plays a key role in the electron transfer to cytochrome P450, which takes part in a wide range of oxidative metabolic reactions in various organisms from microbes to humans. Human CPR was exposed for 60min to 1966-MHz RF inside a transverse electromagnetic cell (TEM-cell) placed in an incubator. The specific absorption rate (SAR) was 5W·kg(-1). Conformation changes have been detected through fluorescent spectroscopy of flavin and tryptophan residues, and investigated through circular dichroism, dynamic light scattering and microelectrophoresis. These showed that CPR was narrowed. By using cytochrome C reductase activity to assess the electron flux through the CPR, the Michaelis Menten constant (Km) and the maximum initial velocity (Vmax) decreased by 22% as compared with controls. This change was due to small changes in the tertiary and secondary structures of the protein at 37°C. The relevance of these findings to an actual RF exposure scenario demands further biochemical and in-vivo confirmation.
[Mh] Termos MeSH primário: Telefone Celular
NADPH-Ferri-Hemoproteína Redutase/química
NADPH-Ferri-Hemoproteína Redutase/metabolismo
Ondas de Rádio/efeitos adversos
[Mh] Termos MeSH secundário: Dinitrocresóis/química
Dinitrocresóis/metabolismo
Transporte de Elétrons/efeitos da radiação
Seres Humanos
Temperatura Ambiente
Triptofano/química
Triptofano/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Dinitrocresols); 1604ZJR09T (4,6-dinitro-o-cresol); 8DUH1N11BX (Tryptophan); EC 1.6.2.4 (NADPH-Ferrihemoprotein Reductase)
[Em] Mês de entrada:1701
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160601
[St] Status:MEDLINE



página 1 de 15 ir para página                         
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde