RESUMO
Acetaldehyde dehydrogenase (AdhE) is a bifunctional acetaldehyde-coenzyme A (CoA) dehydrogenase and alcohol dehydrogenase involved in anaerobic metabolism in gram-negative bacteria. This enzyme was recently found to be a key regulator of the type three secretion (T3S) system in Escherichia coli. AdhE inhibitors can be used as tools to study bacterial virulence and a starting point for discovery of novel antibacterial agents. We developed a robust enzymatic assay, based on the acetaldehyde-CoA dehydrogenase activity of AdhE using both absorption and fluorescence detection models (Z' > 0.7). This assay was used to screen ~11,000 small molecules in 384-well format that resulted in three hits that were confirmed by resynthesis and validation. All three compounds are noncompetitive with respect to acetaldehyde and display a clear dose-response effect with hill slopes of 1-2. These new inhibitors will be used as chemical tools to study the interplay between metabolism and virulence and the role of AdhE in T3S regulation in gram-negative bacteria, and as starting points for the development of novel antibacterial agents.
Assuntos
Álcool Desidrogenase/antagonistas & inibidores , Aldeído Oxirredutases/antagonistas & inibidores , Antibacterianos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Escherichia coli Êntero-Hemorrágica/efeitos dos fármacos , Escherichia coli Êntero-Hemorrágica/enzimologia , Inibidores Enzimáticos/farmacologia , Proteínas de Escherichia coli/antagonistas & inibidores , Álcool Desidrogenase/genética , Álcool Desidrogenase/metabolismo , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Animais , Antibacterianos/química , Linhagem Celular , Relação Dose-Resposta a Droga , Descoberta de Drogas/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , Escherichia coli Êntero-Hemorrágica/genética , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/química , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Humanos , Camundongos , Fluxo de TrabalhoRESUMO
Nitric oxide (NO) contributes to myogenesis by regulating the transition between myoblast proliferation and fusion through cGMP signaling. NO can form S-nitrosothiols (RSNO), which control signaling pathways in many different cell types. However, neither the role of RSNO content nor its regulation by the denitrosylase activity of S-nitrosoglutathione reductase (GSNOR) during myogenesis is understood. Here, we used primary cultures of chick embryonic skeletal muscle cells to investigate whether changes in intracellular RSNO alter proliferation and fusion of myoblasts in the presence and absence of cGMP. Cultures were grown to fuse most of the myoblasts into myotubes, with and without S-nitrosocysteine (CysNO), 8-Br-cGMP, DETA-NO, or inhibitors for NO synthase (NOS), GSNOR, soluble guanylyl cyclase (sGC), or a combination of these, followed by analysis of GSNOR activity, protein expression, RSNO, cGMP, and cell morphology. Although the activity of GSNOR increased progressively over 72 h, inhibiting GSNOR (by GSNOR inhibitor - GSNORi - or by knocking down GSNOR with siRNA) produced an increase in RSNO and in the number of myoblasts and fibroblasts, accompanied by a decrease in myoblast fusion index. This was also detected with CysNO supplementation. Enhanced myoblast number was proportional to GSNOR inhibition. Effects of the GSNORi and GSNOR knockdown were blunted by NOS inhibition, suggesting their dependence on NO synthesis. Interestingly, GSNORi and GSNOR knockdown reversed the attenuated proliferation obtained with sGC inhibition in myoblasts, but not in fibroblasts. Hence myoblast proliferation is enhanced by increasing RSNO, and regulated by GSNOR activity, independently of cGMP production and signaling.
Assuntos
Aldeído Oxirredutases/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Desenvolvimento Muscular/genética , Mioblastos/metabolismo , Óxido Nítrico/metabolismo , Aldeído Oxirredutases/antagonistas & inibidores , Aldeído Oxirredutases/genética , Animais , Diferenciação Celular , Fusão Celular , Embrião de Galinha , AMP Cíclico/metabolismo , AMP Cíclico/farmacologia , GMP Cíclico/análogos & derivados , GMP Cíclico/farmacologia , Cisteína/análogos & derivados , Cisteína/metabolismo , Cisteína/farmacologia , Inibidores Enzimáticos/farmacologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Desenvolvimento Muscular/efeitos dos fármacos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Cultura Primária de Células , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , S-Nitrosoglutationa/metabolismo , S-Nitrosotióis/metabolismo , S-Nitrosotióis/farmacologia , Transdução de Sinais , Guanilil Ciclase Solúvel/genética , Guanilil Ciclase Solúvel/metabolismo , Guanilil Ciclase Solúvel/farmacologia , Tionucleotídeos/farmacologia , Triazenos/farmacologiaRESUMO
S-nitrosoglutathione reductase is the primary enzyme responsible for the metabolism of S-nitrosoglutathione (GSNO), the body's main source of bioavailable nitric oxide. Through its catabolic activity, GSNO reductase (GSNOR) plays a central role in regulating endogenous S-nitrosothiol levels and protein S-nitrosation-based signaling. By inhibiting GSNOR, we aim to increase pulmonary GSNO and induce bronchodilation while reducing inflammation in lung diseases such as asthma. To support the clinical development of N6022, a first-in-class GSNOR inhibitor, a 14-day toxicology study was conducted. Sprague-Dawley rats were given 2, 10 or 50 mg/kg/day N6022 via IV administration. N6022 was well tolerated at all doses and no biologically significant adverse findings were noted in the study up to 10 mg/kg/day. N6022-related study findings were limited to the high dose group. One male rat had mild hepatocellular necrosis with accompanying increases in ALT and AST and several male animals had histological lung assessments with a slight increase in foreign body granulomas. Systemic exposure was greater in males than females and saturation of plasma clearance was observed in both sexes in the high dose group. Liver was identified as the major organ of elimination. Mechanistic studies showed dose-dependent effects on the integrity of a rat hepatoma cell line.
Assuntos
Aldeído Oxirredutases/antagonistas & inibidores , Benzamidas/farmacocinética , Benzamidas/toxicidade , Inibidores Enzimáticos/farmacocinética , Inibidores Enzimáticos/toxicidade , Pirróis/farmacocinética , Pirróis/toxicidade , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Animais , Aspartato Aminotransferases/sangue , Asma/tratamento farmacológico , Benzamidas/sangue , Benzamidas/urina , Bile/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/sangue , Inibidores Enzimáticos/urina , Fezes/química , Feminino , Glutationa/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Pirróis/sangue , Pirróis/urina , Ratos , Ratos Sprague-DawleyRESUMO
Peroxisomes, single-membrane-bounded organelles with essentially oxidative metabolism, are key in plant responses to abiotic and biotic stresses. Recently, the presence of nitric oxide (NO) described in peroxisomes opened the possibility of new cellular functions, as NO regulates diverse biological processes by directly modifying proteins. However, this mechanism has not yet been analysed in peroxisomes. This study assessed the presence of S-nitrosylation in pea-leaf peroxisomes, purified S-nitrosylated peroxisome proteins by immunoprecipitation, and identified the purified proteins by two different mass-spectrometry techniques (matrix-assisted laser desorption/ionization tandem time-of-flight and two-dimensional nano-liquid chromatography coupled to ion-trap tandem mass spectrometry). Six peroxisomal proteins were identified as putative targets of S-nitrosylation involved in photorespiration, ß-oxidation, and reactive oxygen species detoxification. The activity of three of these proteins (catalase, glycolate oxidase, and malate dehydrogenase) is inhibited by NO donors. NO metabolism/S-nitrosylation and peroxisomes were analysed under two different types of abiotic stress, i.e. cadmium and 2,4-dichlorophenoxy acetic acid (2,4-D). Both types of stress reduced NO production in pea plants, and an increase in S-nitrosylation was observed in pea extracts under 2,4-D treatment while no total changes were observed in peroxisomes. However, the S-nitrosylation levels of catalase and glycolate oxidase changed under cadmium and 2,4-D treatments, suggesting that this post-translational modification could be involved in the regulation of H(2)O(2) level under abiotic stress.
Assuntos
Aldeído Oxirredutases/metabolismo , Óxido Nítrico/metabolismo , Peroxissomos/metabolismo , Pisum sativum/fisiologia , Processamento de Proteína Pós-Traducional , Estresse Fisiológico/fisiologia , Ácido 2,4-Diclorofenoxiacético/farmacologia , Oxirredutases do Álcool/metabolismo , Aldeído Oxirredutases/antagonistas & inibidores , Cádmio/farmacologia , Catalase/metabolismo , Malato Desidrogenase/metabolismo , Doadores de Óxido Nítrico/farmacologia , Pisum sativum/enzimologia , Pisum sativum/metabolismo , Peroxissomos/enzimologia , Extratos Vegetais/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Proteínas de Plantas/metabolismo , Proteômica , Espécies Reativas de Oxigênio/metabolismo , S-Nitrosoglutationa/farmacologiaRESUMO
The pyrrole based N6022 was recently identified as a potent, selective, reversible, and efficacious S-nitrosoglutathione reductase (GSNOR) inhibitor and is currently undergoing clinical development for the treatment of acute asthma. GSNOR is a member of the alcohol dehydrogenase family (ADH) and regulates the levels of S-nitrosothiols (SNOs) through catabolism of S-nitrosoglutathione (GSNO). Reduced levels of GSNO, as well as other nitrosothiols (SNOs), have been implicated in the pathogenesis of many diseases including those of the respiratory, cardiovascular, and gastrointestinal systems. Preservation of endogenous SNOs through GSNOR inhibition presents a novel therapeutic approach with broad applicability. We describe here the synthesis and structure-activity relationships (SAR) of novel pyrrole based analogues of N6022 focusing on removal of cytochrome P450 inhibition activities. We identified potent and novel GSNOR inhibitors having reduced CYP inhibition activities and demonstrated efficacy in a mouse ovalbumin (OVA) model of asthma.
Assuntos
Aldeído Oxirredutases/antagonistas & inibidores , Benzamidas/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Imidazóis/síntese química , Imidazóis/farmacologia , Pirróis/farmacologia , Animais , Asma/tratamento farmacológico , Asma/enzimologia , Benzamidas/química , Benzamidas/toxicidade , Inibidores das Enzimas do Citocromo P-450 , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Esquema de Medicação , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacocinética , Inibidores Enzimáticos/toxicidade , Humanos , Imidazóis/farmacocinética , Imidazóis/toxicidade , Pulmão/patologia , Pulmão/fisiopatologia , Camundongos , Estrutura Molecular , Terapia de Alvo Molecular , Nível de Efeito Adverso não Observado , Pirróis/química , Pirróis/toxicidade , Receptores Opioides delta/metabolismo , S-Nitrosoglutationa/metabolismo , Relação Estrutura-AtividadeRESUMO
Chitooligosaccharides (COS), a kind of oligosaccharide made from chitin or chitosan, have been used a popular remedy for hangovers. In this study we investigated the in vitro effect of COS lactate salt on ethanol-induced cytotoxicity and the in vivo effect of short-term COS lactate salt feeding on ethanol-induced hangover. Pretreatment of HepG2 cells with COS lactate salt significantly reduced ethanol-induced cytotoxicity and suppressed generation of reactive oxygen species. In addition, COS lactate salt dose-dependently increased acetaldehyde dehydrogenase (ALDH) activity in vitro and reversed the ALDH inhibition induced by daidzin. Furthermore, oral administration of COS lactate salt (200 mg/kg) for 5 days significantly decreased the blood levels of alcohol and acetaldehyde in ethanol-treated mice. It was also demonstrated that hepatic mitochondrial ALDH activity was significantly increased in COS lactate salt-treated mice. Taken together, these findings indicate that COS lactate salt may have efficacy for the management of alcoholic hangovers.
Assuntos
Aldeído Oxirredutases/metabolismo , Quitosana/farmacologia , Lactatos/farmacologia , Fígado/enzimologia , Oligossacarídeos/farmacologia , Acetaldeído/sangue , Álcool Desidrogenase/metabolismo , Aldeído Desidrogenase/genética , Aldeído-Desidrogenase Mitocondrial , Aldeído Oxirredutases/antagonistas & inibidores , Animais , Sobrevivência Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Etanol/sangue , Etanol/toxicidade , Células Hep G2 , Humanos , Isoflavonas/farmacologia , Masculino , Camundongos , Camundongos Pelados , Mitocôndrias Hepáticas/enzimologia , RNA Mensageiro/análise , Espécies Reativas de Oxigênio/metabolismoRESUMO
The CO dehydrogenase of the eubacterium Oligotropha carboxidovorans is a 277-kDa Mo- and Cu-containing iron-sulfur flavoprotein. Here, the enzyme's active site in the oxidized or reduced state, after inactivation with potassium cyanide or with n-butylisocyanide bound to the active site, has been reinvestigated by multiple wavelength anomalous dispersion measurements at atomic resolution, electron spin resonance spectroscopy, and chemical analyses. We present evidence for a dinuclear heterometal [CuSMoO)OH] cluster in the active site of the oxidized or reduced enzyme, which is prone to cyanolysis. The cluster is coordinated through interactions of the Mo with the dithiolate pyran ring of molybdopterin cytosine dinucleotide and of the Cu with the Sgamma of Cys-388, which is part of the active-site loop VAYRC(388)SFR. The previously reported active-site structure [Dobbek, H., Gremer, L., Meyer, O. & Huber, R. (1999) Proc. Natl. Acad. Sci. USA 96, 8884-8889] of an Mo with three oxygen ligands and an SeH-group bound to the Sgamma atom of Cys-388 could not be confirmed. The structure of CO dehydrogenase with the inhibitor n-butylisocyanide bound has led to a model for the catalytic mechanism of CO oxidation which involves a thiocarbonate-like intermediate state. The dinuclear [CuSMo(O)OH] cluster of CO dehydrogenase establishes a previously uncharacterized class of dinuclear molybdoenzymes containing the pterin cofactor.
Assuntos
Aldeído Oxirredutases/metabolismo , Proteínas de Bactérias/metabolismo , Coenzimas , Complexos Multienzimáticos/metabolismo , Aldeído Oxirredutases/antagonistas & inibidores , Aldeído Oxirredutases/química , Alphaproteobacteria/enzimologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Sítios de Ligação , Catálise , Cobre/química , Espectroscopia de Ressonância de Spin Eletrônica , Inibidores Enzimáticos/farmacologia , Metaloproteínas/química , Modelos Moleculares , Molibdênio/química , Cofatores de Molibdênio , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/química , Nitrilas/química , Nitrilas/farmacologia , Oxirredução , Cianeto de Potássio/farmacologia , Pteridinas/química , Selênio/química , Relação Estrutura-Atividade , Enxofre/químicaRESUMO
The succinic semialdehyde dehydrogenase (SSADH) inhibitory component was isolated from the EtOAc fraction of Lactuca sativa through repeated column chromatography; then, it was identified as phytol, a diterpenoid, based on the interpretation of several spectral data. Incubation of SSADH with the phytol results in a time-dependent loss of enzymatic activity, suggesting that enzyme modification is irreversible. The inactivation followed pseudo-first-order kinetics with the second-rate order constant of 6.15 x 10(-2) mM(-1) min(-1). Complete protection from inactivation was afforded by the coenzyme NAD+, whereas substrate succinic semialdehyde failed to prevent the inactivation of the enzyme; therefore, it seems likely that phytol covalently binds at or near the active site of the enzyme. It is postulated that the phytol is able to elevate the neurotransmitter GABA levels in central nervous system through its inhibitory action on one of the GABA degradative enzymes, SSADH.
Assuntos
Aldeído Oxirredutases/antagonistas & inibidores , Diterpenos/farmacologia , Inibidores Enzimáticos/farmacologia , Lactuca/enzimologia , Fitol/farmacologia , Aldeído Oxirredutases/metabolismo , Animais , Bovinos , Diterpenos/química , Diterpenos/isolamento & purificação , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Fitol/química , Fitol/isolamento & purificação , Componentes Aéreos da Planta/química , Extratos Vegetais/química , Succinato-Semialdeído DesidrogenaseRESUMO
80% Aqueous MeOH extracts from the wood of Caesalpinia sappan, which showed remarkable anticonvulsant activity, were fractionated using EtOAc, n-BuOH, and H2O. Among them, the EtOAc fraction significantly inhibited the activities of two GABA degradative enzymes, succinic semialdehyde dehydrogenase (SSADH) and succinic semialdehyde reductase (SSAR). Repeated column chromatographies for the fraction guided by activity test led to the isolation of the two active principal components. Their chemical structures were determined to be sappanchalcone and brazilin based on spectral data. The pure compounds, sappanchalcone (1) and brazilin (2), inactivated the SSAR activities in a dose dependent manner, whereas SSADH was inhibited partially by sappanchalcone and not by brazilin.
Assuntos
Anticonvulsivantes/isolamento & purificação , Plantas Medicinais/química , Aldeído Oxirredutases/antagonistas & inibidores , Animais , Bovinos , Inibidores Enzimáticos/isolamento & purificação , Hidroxibutirato Desidrogenase/antagonistas & inibidores , Succinato-Semialdeído Desidrogenase , MadeiraRESUMO
The metabolite 5-aminolevulinic acid (ALA) is an early committed intermediate in the biosynthetic pathway of heme and chlorophyll formation. In plants, 5-aminolevulinic acid is synthesized via a two-step pathway in which glutamyl-tRNA(Glu) is reduced by glutamyl-tRNA(Glu) reductase (GluTR) to glutamate 1-semialdehyde, followed by transformation to 5-aminolevulinic acid catalyzed by glutamate 1-semialdehyde aminotransferase. Using an Escherichia coli cell-based high-throughput assay to screen small molecule libraries, we identified several chemical classes that specifically inhibit heme/chlorophyll biosynthesis at this point by demonstrating that the observed cell growth inhibition is reversed by supplementing the medium with 5-aminolevulinic acid. These compounds were further tested in vitro for inhibition of the purified enzymes GluTR and glutamate 1-semialdehyde aminotransferase as confirmation of the specificity and site of action. Several promising compounds were identified from the high-throughput screen that inhibit GluTR with an I(0.5) of less than 10 microM. Our results demonstrate the efficacy of cell-based high-throughput screening for identifying inhibitors of 5-aminolevulinic acid biosynthesis, thus representing the first report of exogenous inhibitors of this enzyme.
Assuntos
Aldeído Oxirredutases/antagonistas & inibidores , Aldeído Oxirredutases/metabolismo , Clorofila/biossíntese , Inibidores Enzimáticos/farmacologia , Heme/biossíntese , Ácido Aminolevulínico/metabolismo , Ácido Aminolevulínico/farmacologia , Arabidopsis/genética , Ácidos Cicloexanocarboxílicos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/classificação , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Glutamatos/metabolismo , Hordeum/enzimologia , Hordeum/genética , Concentração Inibidora 50 , Transferases Intramoleculares/antagonistas & inibidores , Transferases Intramoleculares/metabolismo , Cinética , Mutação/genética , RNA de Transferência de Glutamina/metabolismo , Proteínas Recombinantes de Fusão/antagonistas & inibidores , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Reprodutibilidade dos Testes , Homologia de Sequência de Aminoácidos , Spinacia oleracea/genética , Especificidade por SubstratoRESUMO
Although 7-hydroxymethotrexate is a major metabolite of methotrexate during high-dose therapy, negligible methotrexate-oxidizing activity has been found in-vitro in the liver in man. The goals of this study were to determine the role of aldehyde oxidase in the metabolism of methotrexate to 7-hydroxymethotrexate in the liver and to study the effects of inhibitors and other substrates on the metabolism of methotrexate. Methotrexate, (+/-)-methotrexate and (-)-methotrexate were incubated with partially purified aldehyde oxidase from the liver of rabbit, guinea-pig and man and the products analysed by HPLC. Rabbit liver aldehyde oxidase was used for purposes of comparison. In-vitro aldehyde oxidase from the liver of man catalyses the oxidation of methotrexate to 7-hydroxymethotrexate, but the turnover is low. However, formation of 7-hydroxy-methotrexate from all forms of methotrexate by the liver in guinea-pig and man was significantly inhibited in the presence of 100 microM menadione and chlorpromazine, potent inhibitors of aldehyde oxidase. Allopurinol (100 microM) had a negligible inhibitory effect on liver aldehyde oxidase from guinea-pig and man. Allopurinol is a xanthine oxidase inhibitor. The production of 7-hydroxymethotrexate was enhanced in the presence of allopurinol. Although aldehyde oxidase is also responsible for some of this conversion, it is also possible that the closely related xanthine oxidase is responsible for the formation of 7-hydroxymethotrexate. By employing potent selective inhibitors of aldehyde oxidase, menadione and chlorpromazine, we have demonstrated for the first time that liver aldehyde oxidase from man is minimally involved in methotrexate oxidation.
Assuntos
Aldeído Oxirredutases/metabolismo , Fígado/metabolismo , Metotrexato/metabolismo , Aciclovir/análogos & derivados , Aciclovir/metabolismo , Aldeído Oxidase , Aldeído Oxirredutases/antagonistas & inibidores , Alopurinol/farmacologia , Animais , Clorpromazina/farmacologia , Inibidores Enzimáticos/farmacologia , Guanina , Cobaias , Humanos , Cinética , Fígado/enzimologia , Metotrexato/análogos & derivados , Metotrexato/química , Oxirredução , Coelhos , Especificidade da Espécie , Estereoisomerismo , Especificidade por Substrato , Vitamina K/farmacologiaRESUMO
In our search for the anticonvulsant constituent of Gastrodia elata repeated column chromatographies guided by activity assay led to isolation of an active compound, which was identified as gastrodin on the basis of spectral data. Brain succinic semialdehyde dehydrogenase (SSADH) was inactivated by preincubation with gastrodin in a time-dependent manner and the reaction was monitored by absorption and fluorescence spectroscopic methods. The inactivation followed pseudo-first-order kinetics with the second-rate order constant of 1.2 x 10(3) M-1min-1. The time course of the reaction was significantly affected by the coenzyme NAD+, which affected complete protection against the loss of the catalytic activity, whereas substrate succinic semialdehyde failed to prevent the inactivation of the enzyme. It is postulated that the gastrodin is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on one of the GABA degradative enzymes, SSADH.
Assuntos
Aldeído Oxirredutases/antagonistas & inibidores , Anticonvulsivantes/isolamento & purificação , Álcoois Benzílicos , Inibidores Enzimáticos/isolamento & purificação , Glucosídeos/isolamento & purificação , Plantas Medicinais/química , Animais , Bovinos , Succinato-Semialdeído Desidrogenase , Ácido gama-Aminobutírico/metabolismoRESUMO
N-formylglycine was developed as a dead-end inhibitor of the succinic semialdehyde dehydrogenase reaction. At 4 mM, it inhibited Aspergillus niger succinic semialdehyde dehydrogenase by 40%. N-formylglycine is a reversible, complete inhibitor; the inhibition is competitive with succinic semialdehyde and uncompetitive with respect to NAD+ and the Ki values are 4.9 and 10.4 mM respectively. Potato succinic semialdehyde dehydrogenase is also inhibited by N-formylglycine to a similar extent, the nature of the inhibition being identical to that observed with the A. niger enzyme.
Assuntos
Aldeído Oxirredutases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Glicina/análogos & derivados , Aspergillus niger/enzimologia , Glicina/farmacologia , Solanum tuberosum/enzimologia , Succinato-Semialdeído DesidrogenaseRESUMO
Liver aldehyde oxidase (EC 1.2.3.1) was capable of reducing N-arylacetohydroxamic acids, N-hydroxy-2-acetyl-aminofluorene, N-hydroxy-4-acetylaminobiphenyl and N-hydroxyphenacetin, to the corresponding amides in the presence of an electron donor of the enzyme under anaerobic conditions. When supplemented with an electron donor of the enzyme, a significant reduction of N-hydroxy-2-acetylaminofluorene occurred, which was sensitive to an inhibitor of the enzyme. These observations were made with cytosolic fractions prepared from the livers of rabbits, guinea pigs, rats and mice.
Assuntos
Aldeído Oxirredutases/metabolismo , Compostos de Aminobifenil/metabolismo , Ácidos Hidroxâmicos/metabolismo , Hidroxiacetilaminofluoreno/metabolismo , Fígado/enzimologia , Fenacetina/análogos & derivados , Aldeído Oxidase , Aldeído Oxirredutases/antagonistas & inibidores , Aldeídos , Animais , Carcinógenos/metabolismo , Cobaias , Fígado/metabolismo , Camundongos , Oxirredução , Fenacetina/metabolismo , Coelhos , Ratos , Vitamina K/farmacologiaRESUMO
The present paper describes that mammalian liver aldehyde oxidase is involved in the reduction of nicotinamide N-oxide to nicotinamide. Rabbit liver aldehyde oxidase supplemented with its electron donor exhibited a significant nicotinamide N-oxide reductase activity under anaerobic conditions. Liver cytosols from rabbits, hogs, guinea pigs, hamsters, rats and mice, all of them, similarly exhibited the N-oxide reductase activity in the presence of an electron donor of aldehyde oxidase, but not xanthine oxidase. The cytosolic N-oxide reductase activity was almost completely inhibited by menadione, an inhibitor of aldehyde oxidase.