AASERT 97 - Role of Clostridial Reducing Power in Nitroaryl Compound Degradation

2001 ◽  
Author(s):  
Ronald Crawford
Keyword(s):  
Reducing Power

Ozone risk assessment for plants: Central role of metabolism-dependent changes in reducing power

2008 ◽  
Vol 156 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Pierre Dizengremel ◽  
Didier Le Thiec ◽  
Matthieu Bagard ◽  
Yves Jolivet
Keyword(s):  
Risk Assessment ◽  
Reducing Power ◽  
Ozone Risk Assessment

scholarly journals The Bacillus subtilis yqjI Gene Encodes the NADP+-Dependent 6-P-Gluconate Dehydrogenase in the Pentose Phosphate Pathway

2004 ◽  
Vol 186 (14) ◽  
pp. 4528-4534 ◽  
Author(s):  
Nicola Zamboni ◽  
Eliane Fischer ◽  
Dietmar Laudert ◽  
Stéphane Aymerich ◽  
Hans-Peter Hohmann ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Glucose Dehydrogenase ◽  
Reducing Power ◽  
Pentose Phosphate ◽  
Gene Encoding ◽  
Metabolic Intermediates ◽  
The Third ◽  
Key Enzyme ◽  
Sequence Similarities

ABSTRACT Despite the importance of the oxidative pentose phosphate (PP) pathway as a major source of reducing power and metabolic intermediates for biosynthetic processes, almost no direct genetic or biochemical evidence is available for Bacillus subtilis. Using a combination of knockout mutations in known and putative genes of the oxidative PP pathway and 13C-labeling experiments, we demonstrated that yqjI encodes the NADP+-dependent 6-P-gluconate dehydrogenase, as was hypothesized previously from sequence similarities. Moreover, YqjI was the predominant isoenzyme during glucose and gluconate catabolism, and its role in the oxidative PP pathway could not be played by either of two homologues, GntZ and YqeC. This conclusion is in contrast to the generally held view that GntZ is the relevant isoform; hence, we propose a new designation for yqjI, gndA, the monocistronic gene encoding the principal 6-P-gluconate dehydrogenase. Although we demonstrated the NAD+-dependent 6-P-gluconate dehydrogenase activity of GntZ, gntZ mutants exhibited no detectable phenotype on glucose, and GntZ did not contribute to PP pathway fluxes during growth on glucose. Since gntZ mutants grew normally on gluconate, the functional role of GntZ remains obscure, as does the role of the third homologue, YqeC. Knockout of the glucose-6-P dehydrogenase-encoding zwf gene was primarily compensated for by increased glycolytic fluxes, but about 5% of the catabolic flux was rerouted through the gluconate bypass with glucose dehydrogenase as the key enzyme.

Reducing power of ferrous iron in the Archean Ocean, 2. Role of FEOH+photooxidation

1987 ◽  
Vol 2 (4) ◽  
pp. 395-408 ◽  
Author(s):  
L. M. François
Keyword(s):  
Ferrous Iron ◽  
Reducing Power

Cloning and characterization of a thermostable glutathione reductase from a psychrophilic Arctic bacterium Sphingomonas sp.

2019 ◽  
Author(s):  
Hai VuThi ◽  
Sei-Heon Jang ◽  
ChangWoo Lee
Keyword(s):  
Thermal Stability ◽  
Glutathione Reductase ◽  
Redox Homeostasis ◽  
Residual Activity ◽  
Reducing Power ◽  
Composition Analysis ◽  
Psychrophilic Bacterium ◽  
Tertiary Structures

Abstract Glutathione reductase is an important oxidoreductase that helps maintain redox homeostasis by catalyzing the conversion of glutathione disulfide to glutathione using NADPH as a cofactor. In this study, we cloned and characterized a glutathione reductase (referred hereafter to as SpGR) from Sphingomonas sp. PAMC 26621, an Arctic bacterium. SpGR comprises 449 amino acids, and functions as a dimer. Surprisingly, SpGR exhibits characteristics of thermophilic enzymes, showing optimum activity at 60°C and thermal stability up to 70 °C with approximately 50% residual activity at 70 °C for 2 h. The amino acid composition analysis of SpGR showed a 1.9-fold higher Arg content (6%) and a 2.7-fold lower Lys/Arg ratio (0.75) compared to the Arg content (3.15%) and the Lys/Arg ratio (2.01) of known psychrophilic glutathione reductases. SpGR also exhibits its activity at 4°C, and circular dichroism and fluorescence spectroscopy results indicate that SpGR maintains its secondary and tertiary structures within the temperature range 4–70°C. Taken together, the results of this study indicate that despite its origin from a psychrophilic bacterium, SpGR has high thermal stability. Our study provides an insight into the role of glutathione reductase in maintaining the reducing power of an Arctic bacterium in a broad range of temperatures.

scholarly journals The Role of C-8 OH on the Antioxidant Activity of Norwogonin and Isowogonin

2020 ◽  
Vol 15 (5) ◽  
pp. 1934578X2092488
Author(s):  
Qiushan Zhang ◽  
Jin Shao ◽  
Tong Zhao ◽  
Lei He ◽  
Huiping Ma ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ferrous Iron ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Iron Chelation ◽  
Reducing Power ◽  
Antioxidant Property ◽  
Hydroxyl Group ◽  
Total Antioxidant

In the present study, the antioxidant property of 4 flavones (moslosooflavone, wogonin, isowogonin, and norwogonin) was evaluated using 6 different assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH·), superoxide (O2 •−), and nitric oxide (NO) radical scavenging assays, ferrous iron chelation, reducing power, and total antioxidant capacity. The 4 flavones exhibited antioxidant activities with decreasing order as norwogonin > isowogonin >> wogonin> moslosooflavone. The present results demonstrated that norwogonin and isowogonin exhibited excellent antioxidant activity, which was mainly based on the presence of C-8 hydroxyl group.

The role of magnetic nanoparticles (MNP) as reducing agents in an MNP-supported Pd–catalyst for the reductive homocoupling of aryl halides

2012 ◽  
Vol 90 (1) ◽  
pp. 138-144 ◽  
Author(s):  
Jie Zheng ◽  
Shengyue Lin ◽  
Bi-Wang Jiang ◽  
Todd B. Marder ◽  
Zhen Yang
Keyword(s):  
Magnetic Nanoparticles ◽  
Aryl Halide ◽  
Reducing Power ◽  
Cross Coupling ◽  
Reducing Agent ◽  
Aryl Halides ◽  
Pd Catalyst ◽  
Reductive Homocoupling ◽  
Supported Pd

A palladium pincer catalyst grafted onto the surface of magnetic nanoparticles (MNPs) has been developed. This material effectively catalyzes the reductive homocoupling of various aryl halide substrates, with the MNP support acting as the reducing agent. The catalyst can be recycled up to five times in the absence of additional reducing agent to give almost quantitative yields of biaryl homocoupling products. After the reducing power of the MNP has been depleted, the supported Pd complex remains an effective catalyst for Suzuki–Miyaura cross-coupling.

scholarly journals Use of response surface methodology to evaluate the reducing power in binary solutions of ascorbic acid with natural polyphenolic antioxidants

2013 ◽  
Vol 2 (2) ◽  
Author(s):  
Marie Aoun ◽  
Dimitris P Makris
Keyword(s):  
Ascorbic Acid ◽  
Reducing Power ◽  
Antioxidant Response ◽  
Simple Linear Regression ◽  
Reliable Prediction ◽  
Mixture Effects ◽  
Natural Polyphenols ◽  
Regression Approach ◽  
Simultaneous Variation

Natural polyphenols, ferulic acid (FA) and hesperetin (Hp) were tested for their Fe3+-reducing power, using the TPTZ methodology, as a first step to rank them according to their antioxidant potential. Ranking also included quercetin (Qt), a very well-studied natural, polyphenolic antioxidant, and ascorbic acid (AA). All phenolics considered were also tested in binary mixtures with AA, to illustrate possible mixture effects. By employing a simple linear regression approach, combinations of AA / Qt and AA / Hp were shown to result in antagonistic effects, whereas in mixtures of AA / FA, synergism was observed. To thoroughly investigate the role of the relative concentrations of the antioxidants, a 3×3 factorial design was implemented. This approach enabled the recording of the response (reducing power) upon simultaneous variation of concentrations of both antioxidants in the mixtures, and revealed only antagonism for every combination tested. It is proposed that in similar investigations factorial designs need to be implemented for reliable prediction of the antioxidant response(s) within appropriate limits. This is particularly crucial for antioxidants that are destined to be added in food matrices, where maximal antioxidant protection is always sought.

scholarly journals NAD(P)H Drives the Ascorbate–Glutathione Cycle and Abundance of Catalase in Developing Beech Seeds Differently in Embryonic Axes and Cotyledons

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2021
Author(s):  
Ewa Marzena Kalemba ◽  
Shirin Alipour ◽  
Natalia Wojciechowska
Keyword(s):  
Seed Quality ◽  
Redox Homeostasis ◽  
Reducing Power ◽  
European Beech ◽  
Embryonic Axes ◽  
Lowland Forests ◽  
Glutathione Cycle ◽  
Glutathione Enzymes ◽  
Redox Forms

European beech is an important component of European lowland forests in terms of ecology, and produces irregular seeds categorized as intermediate due to their limited longevity. Removal of the excess of reactive oxygen species is crucial for redox homeostasis in growing plant tissues. Hydrogen peroxide (H2O2) is detoxified via the plant-specific ascorbate-glutathione cycle, and enzymatically, mainly by catalase (CAT). The reduced and oxidized (redox) forms of ascorbate (AsA, DHA) and glutathione (GSH, GSSG) decreased during maturation as the content of redox forms of nicotinamide adenine dinucleotide (NADH, NAD+) phosphate (NADPH, NADP+), cofactors of ascorbate–glutathione enzymes, declined and limited this cycle. The degree of oxidation of glutathione peaked at approximately 80%, at the exact time when the NADP content was the lowest and the NADPH/NADP+ ratio reached the highest values. The glutathione pool was reflected in changes in the NADP pool, both in embryonic axes (R2 = 0.61) and in cotyledons (R2 = 0.98). A large excess of NADPH was reported in embryonic axes, whereas cotyledons displayed more unified levels of NADP redox forms. As a result, anabolic redox charge and reducing power were higher in embryonic axes. CAT was recognized as two proteins, and the abundance of the 55 kDa protein was correlated with all redox forms of ascorbate, glutathione, NAD, and NADP, whereas the 37 kDa protein was oppositely regulated in embryonic axes and cotyledons. Here, we discuss the role of NAD(P) in the regulation of the ascorbate–glutathione cycle, catalase, and seed longevity concerning a putative role of NAD(P)H as a redox biomarker involved in predefining seed quality, because NAD(P)H-derived redox homeostasis was found to be better controlled in embryonic axes than cotyledons.

Use of Nitroxide Spin Probes and Electron Paramagnetic Resonance for Assessing Reducing Power of Beer. Role of SH Groups

2005 ◽  
Vol 53 (4) ◽  
pp. 1052-1057 ◽  
Author(s):  
Nikolai M. Kocherginsky ◽  
Yuri Yu. Kostetski ◽  
Alex I. Smirnov
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Reducing Power ◽  
Spin Probes ◽  
Paramagnetic Resonance ◽  
Sh Groups ◽  
Nitroxide Spin Probes ◽  
Electron Paramagnetic
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