Redox Reactions Catalyzed by Isolated Enzymes

Monti, Daniela; Ottolina, Gianluca; Carrea, Giacomo; Riva, Sergio

doi:10.1021/cr100334x

Cited by 210 publications

(149 citation statements)

References 346 publications

Supporting

Mentioning

143

Contrasting

Unclassified

Order By: Relevance

“…There are a number of redox reactions in the cell (Monti et al, 2011), in which radicals or radical pairs appear as intermediates. Radicals activate various signaling pathways that regulate a number of cellular processes such as gene expression and apoptosis (Buetler et al, 2004;Shen and Liu, 2005).…”

Section: Discussionmentioning

confidence: 99%

Effect of 50-Hz Sinusoidal Magnetic Field on the Production of Superoxide Anion and the Expression of Heat-shock Protein 70 in RAW264 Cells

Pooam¹,

Nakayama²,

Nishigaki³

et al. 2017

IJC

View full text Add to dashboard Cite

There is a growing concern if the power-line frequency (50/60 Hz) magnetic field (termed in this paper ELF-MF) increases cancer risks. Since one of the major causes of cancer is cellular oxidative stress, whether the ELF-MF increases the oxidative stress is a central problem in the studies on the biological effect of the ELF-MF. Here, we have investigated the effect of 50-Hz sinusoidal magnetic field on the production of O 2 -, the expression of heat shock protein (HSP) 70 and the mitochondrial membrane potential in cell line macrophage RAW264 cells. Macrophages were exposed to or not exposed to 0.1-mT or 0.5-mT, 50-Hz sinusoidal magnetic field and were subjected to (1) assay for O 2 -(2) analysis of the expression of HSP70, and (3) measurement of the mitochondrial membrane potential with a fluorescent indicator. The 50-Hz magnetic field enhanced production of O 2 -and the expression of HSP70, both of which are consistent with previous studies. The exposure to 50-Hz magnetic field decreased mitochondrial membrane potential indicating the diminished activity of mitochondria. The uncoupler of mitochondrial function, carbonyl cyanide p-trifluoromethoxyphenylhydrazone diminished the membrane potential, as expected. On the other hand, it increased the production of O 2 -. The results collectively suggest that the 50-Hz magnetic field diminished the mitochondrial membrane potential, which led to the increase in the production of O 2 -and the expression of HSP70 protein.

show abstract

Section: Discussionmentioning

confidence: 99%

Effect of 50-Hz Sinusoidal Magnetic Field on the Production of Superoxide Anion and the Expression of Heat-shock Protein 70 in RAW264 Cells

Pooam¹,

Nakayama²,

Nishigaki³

et al. 2017

IJC

View full text Add to dashboard Cite

show abstract

“…32 88À89). 1 (S). Quantification of 1c/2c was performed by reverse-phase HPLC, using a calibration curve (Nucleosil 100 (C18) column, 50% acetonitrile and 50% 50 mM potassium phosphate buffer, pH 2.0, flow 1 mL/min (retention times (min): 8.5 (2c); 29.5 (1c)).…”

Section: ' Conclusionmentioning

confidence: 99%

Dynamic Kinetic Resolution Process Employing Haloalkane Dehalogenase

et al. 2011

View full text Add to dashboard Cite

The first dynamic kinetic resolution process with a haloalkane dehalogenase is described, allowing the efficient preparation of enantiopure α-hydroxyamides from racemic α-bromoamides. A simple membrane reactor is used to separate the enzyme from the nonsoluble, polymer-based, and metal-free racemizing agent. A model substrate, N-phenyl-2-bromopropionamide, was converted to (S)-N-phenyl-2-hydroxypropionamide either with 63% yield and 95% e.e or with 78% yield and 88% e.e.

show abstract

“…In this work we studied the underlying principles for an efficient and stable enzymatic regeneration process of NAD(P) + , which does not show the restrictions of alternative systems, e.g. electrochemical methods [3]. Coenzymes are costly [4], which makes them too expensive to employ more than the minimal amount that still guarantees fast conversion of the Abbreviations: ABTS, 2,2 -azinobis-(3-ethylbenzothiazoline-6-sulfonic acid); GLC, d-glucose; GL, d-glucono-1,5-lactone; GA, gluconic acid; NAD(P)H, nicotinamide adenine dinucleotide (phosphate); O2, molecular oxygen; SHE, standard hydrogen electrode; STY, space-time yield (mM h −1 ).…”

Section: Introductionmentioning

confidence: 99%

Engineering an enzymatic regeneration system for NAD(P)H oxidation

Pham

Hollmann

Kracher

et al. 2015

Journal of Molecular Catalysis B: Enzymatic

View full text Add to dashboard Cite

a b s t r a c tA recently proposed coenzyme regeneration system employing laccase and a number of various redox mediators for the oxidation of NAD(P)H was studied in detail by kinetic characterization of individual reaction steps. Reaction engineering by modeling was used to optimize the employed enzyme, coenzyme as well as redox mediator concentrations. Glucose dehydrogenase from Bacillus sp. served as a convenient model of synthetic enzymes that depend either on NAD + or NADP + . The suitability of laccase from Trametes pubescens in combination with acetosyringone or syringaldazine as redox mediator was tested for the regeneration (oxidation) of both coenzymes. In a first step, pH profiles and catalytic constants of laccase for the redox mediators were determined. Then, second-order rate constants for the oxidation of NAD(P)H by the redox mediators were measured. In a third step, the rate equation for the entire enzymatic process was derived and used to build a MATLAB model. After verifying the agreement of predicted vs. experimental data, the model was used to calculate different scenarios employing varying concentrations of regeneration system components. The modeled processes were experimentally tested and the results compared to the predictions. It was found that the regeneration of NADH to its oxidized form was performed very efficiently, but that an excess of laccase activity leads to a high concentration of the oxidized form of the redox mediator -a phenoxy radical -which initiates coupling (dimerization or polymerization) and enzyme deactivation.

show abstract

Redox Reactions Catalyzed by Isolated Enzymes

Cited by 210 publications

References 346 publications

Effect of 50-Hz Sinusoidal Magnetic Field on the Production of Superoxide Anion and the Expression of Heat-shock Protein 70 in RAW264 Cells

Effect of 50-Hz Sinusoidal Magnetic Field on the Production of Superoxide Anion and the Expression of Heat-shock Protein 70 in RAW264 Cells

Dynamic Kinetic Resolution Process Employing Haloalkane Dehalogenase

Engineering an enzymatic regeneration system for NAD(P)H oxidation

Contact Info

Product

Resources

About