نتایج جستجو برای: quinone

تعداد نتایج: 5334  

2003
HARRY WAGREICH J. M. NELSON

It was only natural that the earlier investigators of the action of the oxidase, tyrosinase, on catechol should have assumed that the first stage in the reaction is the formation of o-quinone. More recently this view of the reaction has gained additional approval from the studies carried on by Pugh and Raper (1). One of the difficulties encountered in trying to determine the nature of the initi...

Journal: :Digital discovery 2023

Computational high-throughput is used to evaluate proton–electron transfer reactions of quinone-type compounds that are potentially useful for energy storage.

2014
Takahiro Yano Maryam Rahimian Kawalpreet K. Aneja Norman M. Schechter Harvey Rubin Charles P. Scott

Type II NADH-quinone oxidoreductase (NDH-2) catalyzes the transfer electrons from NADH to the quinone pool and plays an essential role in the oxidative phosphorylation system of Mycobacterium tuberculosis (Mtb). The absence of NDH-2 in the mammalian mitochondrial electron transport chain makes this enzyme an attractive target for antibiotic development. To fully establish the kinetic properties...

Journal: :Toxicology 2004
Chester E Rodriguez Masaru Shinyashiki John Froines Rong Chun Yu Jon M Fukuto Arthur K Cho

The toxicity of quinones is generally thought to occur by two mechanisms: the formation of covalent bonds with biological molecules by Michael addition chemistry and the catalytic reduction of oxygen to superoxide and other reactive oxygen species (ROS) (redox cycling). In an effort to distinguish between these general mechanisms of toxicity, we have examined the toxicity of five quinones to ye...

Journal: :Physical chemistry chemical physics : PCCP 2017
Liuchuan Tong Qing Chen Andrew A Wong Rafael Gómez-Bombarelli Alán Aspuru-Guzik Roy G Gordon Michael J Aziz

Quinone-based aqueous flow batteries provide a potential opportunity for large-scale, low-cost energy storage due to their composition from earth abundant elements, high aqueous solubility, reversible redox kinetics and their chemical tunability such as reduction potential. In an operating flow battery utilizing 9,10-anthraquinone-2,7-disulfonic acid, the aggregation of an oxidized quinone and ...

Journal: :The Journal of pharmacology and experimental therapeutics 2007
Ji Man Han Yong Jin Lee So Yeon Lee Eun Mee Kim Younghye Moon Ha Won Kim Onyou Hwang

Parkinson's disease (PD) is a progressive neurodegenerative disorder with a selective loss of dopaminergic neurons in the substantia nigra. Evidence suggests oxidation of dopamine (DA) to DA quinone and consequent oxidative stress as a major factor contributing to this vulnerability. We have previously observed that exposure to or induction of NAD(P)H:quinone reductase (QR1), the enzyme that ca...

Journal: :Drug metabolism and disposition: the biological fate of chemicals 1999
H Yamazaki A Shibata M Suzuki M Nakajima N Shimada F P Guengerich T Yokoi

Troglitazone, a new oral antidiabetic drug, is reported to be mostly metabolized to its conjugates and not to be oxidized by cytochrome P-450 (P-450) enzymes. Of fourteen cDNA-expressed human P-450 enzymes examined, CYP1A1, CYP2C8, CYP2C19, and CYP3A4 were active in catalyzing formation of a quinone-type metabolite at a concentration of 10 microM troglitazone, whereas CYP3A4 had the highest cat...

Journal: :The Biochemical journal 1992
M Sugumaran H Dali V Semensi

Mushroom tyrosinase, which is known to convert a variety of o-diphenols into o-benzoquinones, has been shown to catalyse an unusual oxidative decarboxylation of 3,4-dihydroxymandelic acid to 3,4-dihydroxybenzaldehyde [Sugumaran (1986) Biochemistry 25, 4489-4492]. The mechanism of this reaction was re-investigated. Although visible-region spectral studies of the reaction mixture containing 3,4-d...

2013
Wim F. J. Vermaas

Many inhibitors prevent the oxidation o f the primary electron-accepting quinone (QA) by the secondary quinone (QB) in photosystem II by displacem ent o f Q B from its binding site. On the other hand, plastoquinone-1 and 6-azido-5-decyl-2,3-dim ethoxy-/?-benzoquinone displace herbicides. Binding studies show the herbicide/quinone interaction to be (apparently) competitive. The herbicide binding...

Journal: :Journal of environmental management 2012
Tony Hadibarata Risky Ayu Kristanti

The biodegradation of benzo[a]pyrene (BaP) by using Polyporus sp. S133, a white-rot fungus isolated from oil-contaminated soil was investigated. Approximately 73% of the initial concentration of BaP was degraded within 30 d of incubation. The isolation and characterization of 3 metabolites by thin layer chromatography, column chromatography, and UV-vis spectrophotometry in combination with gas ...

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