نتایج جستجو برای: quinone

تعداد نتایج: 5334  

Journal: :The Journal of biological chemistry 2009
Jonathan Ruprecht Victoria Yankovskaya Elena Maklashina So Iwata Gary Cecchini

Three new structures of Escherichia coli succinate-quinone oxidoreductase (SQR) have been solved. One with the specific quinone-binding site (Q-site) inhibitor carboxin present has been solved at 2.4 A resolution and reveals how carboxin inhibits the Q-site. The other new structures are with the Q-site inhibitor pentachlorophenol and with an empty Q-site. These structures reveal important detai...

2012
Wenjie Ye Uthpala I. Seneviratne Ming-Wei Chao Kodihalli C. Ravindra Gerald N. Wogan Steven R. Tannenbaum Paul L. Skipper

Aminophenols can redox cycle through the corresponding quinone imines to generate ROS. The electrophilic quinone imine intermediate can react with protein thiols as a mechanism of immobilization in vivo. Here, we describe the previously unkown transimination of a quinone imine by lysine as an alternative anchoring mechanism. The redox properties of the condensation product remain largely unchan...

Journal: :Journal of the American Chemical Society 2014
Alison E Wendlandt Shannon S Stahl

Copper amine oxidases are a family of enzymes with quinone cofactors that oxidize primary amines to aldehydes. The native mechanism proceeds via an iminoquinone intermediate that promotes high selectivity for reactions with primary amines, thereby constraining the scope of potential biomimetic synthetic applications. Here we report a novel bioinspired quinone catalyst system consisting of 1,10-...

Journal: :The Journal of biological chemistry 1992
L M Nutter E O Ngo G R Fisher P L Gutierrez

Menadione (MD; 2-methyl-1,4-naphthoquinone), a redox cycling quinone was shown to induce single (ss)- and double (ds)-strand DNA breaks in human MCF-7 cells. This DNA damage was mediated via the hydroxyl radical as evidenced by electron spin resonance spectroscopy (ESR) studies utilizing the spin trap, 5,5-dimethyl-1-pyrroline-1-oxide. The free radical production and DNA damage were shown to pl...

Journal: :Biochimica et biophysica acta 2002
André Verméglio Pierre Joliot

This minireview summarizes our present view of the supramolecular organization of the photosynthetic apparatus of Rhodobacter sphaeroides and Rhodobacter capsulatus. These two species present a close association between two reaction centers (RCs), one cytochrome (cyt) bc(1) and one cyt c. In R. sphaeroides, the RCs are only partially surrounded by LH1 complexes. This open ring of LH1 complexes ...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2018
Jiying Pei Yinghui Wang Kefu Yu

Quinones are a class of compounds having substantial toxicity and pharmacological function. This work has produced a derivatization method for quinone detection with high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS). Through introducing tags (methoxy) to the quinone structures, the ionization efficiencies of five quinones (p-benzoquinone (B...

Journal: :Cancer research 1983
A Begleiter

Many clinically useful antitumor agents have a quinone group in their structure. A series of model compounds has been studied to determine if the quinone group is involved in the cytotoxic activity of these agents and to investigate the mechanism of this action. Hydrolyzed benzoquinone mustard, which contains a quinone group, produced significant cell kill of L5178Y lymphoblasts, whereas hydrol...

Journal: :Environmental science & technology 2002
Lisa Klapper Diane M McKnight J Robin Fulton Elizabeth L Blunt-Harris Kelly P Nevin Derek R Lovley Patrick G Hatcher

Humic substances are a heterogeneous class of moderate molecular weight, yellow-colored biomolecules present in all soils, sediments, and natural waters. Although humic substances are generally resistant to microbial degradation under anaerobic conditions, some microorganisms in soils and sediments can use quinone moieties in humic substances as electron acceptors. Laboratory experiments have s...

Journal: :Carcinogenesis 1998
K Faulkner R Mithen G Williamson

The putative anticarcinogenic activity of Brassica vegetables has been associated with the presence of certain glucosinolates. 4-Methylsulphinylbutyl isothiocyanate (sulphoraphane), derived from the corresponding glucosinolate found in broccoli, has previously been identified as a potent inducer of the anticarcinogenic marker enzyme quinone reductase [NADP(H):quinone-acceptor oxidoreductase] in...

Journal: :Journal of the American Chemical Society 2002
Youngeun Kwon Milan Mrksich

This paper describes a physical organic study of the relationship between the rate for an interfacial Diels-Alder reaction and the steric environment around the reacting molecules. The study used as a model reaction the cycloaddition of cyclopentadiene with a self-assembled monolayer (SAM) presenting benzoquinone groups surrounded by hydroxyl-terminated alkanethiolates. The accessibility of the...

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