scholarly journals Cellular Zn depletion by metal ion chelators (TPEN, DTPA and chelex resin) and its application to osteoblastic MC3T3-E1 cells

2007 ◽  
Vol 1 (1) ◽  
pp. 29 ◽  
Author(s):  
Young-Eun Cho ◽  
Ria-Ann R. Lomeda ◽  
Sang-Hoon Ryu ◽  
Jong-Hwa Lee ◽  
John H. Beattie ◽  
...  
Keyword(s):  
Metal Ion ◽  
Chelex Resin ◽  
Metal Ion Chelators

Flavonols as metal-ion chelators: complex formation with Mg2+ and Ba2+ cations in the excited state

1999 ◽  
Vol 127 (1-3) ◽  
pp. 89-100 ◽  
Author(s):  
A.D. Roshal ◽  
A.V. Grigorovich ◽  
A.O. Doroshenko ◽  
V.G. Pivovarenko ◽  
A.P. Demchenko
Keyword(s):  
Excited State ◽  
Complex Formation ◽  
Metal Ion ◽  
Metal Ion Chelators

The Influence of Different Metal-Chelators on the Biological Profile of Nanoparticles for Gallium-68 Based Molecular Imaging

2012 ◽  
Vol 20 ◽  
pp. 21-31 ◽  
Author(s):  
Quinn K.T. Ng ◽  
Tatiana Segura ◽  
Anat Ben-Shlomo ◽  
Thomas Krause ◽  
Thomas L. Mindt ◽  
...  
Keyword(s):  
Surface Modification ◽  
Molecular Imaging ◽  
Metal Ion ◽  
Biological Effects ◽  
Metal Chelators ◽  
Biological Profile ◽  
Positron Emission ◽  
Pharmacokinetic Properties ◽  
Gallium 68 ◽  
Metal Ion Chelators

The use of metal chelators is becoming increasingly important in the development of new tracers for molecular imaging. With the rise of the field of nanotechnology, the fusion of both technologies has shown great potential for clinical applications. The pharmacokinetcs of nanoparticles can be monitored via positron emission tomography (PET) after surface modification and radiolabeling with positron emitting radionuclides. Different metal ion chelators can be used to facilitate labeling of the radionuclides and as a prerequisite, optimized radiolabeling procedure is necessary to prevent nanoparticle aggregation and degradation. However, the effects of chelator modification on nanoparticle pharmacokinetic properties have not been well studied and currently no studies to date have compared the biological effects of the use of different chelators in the surface modification of nanoparticles.

scholarly journals Alloxan-induced luminol luminescence as a tool for investigating mechanisms of radical-mediated diabetogenicity

1981 ◽  
Vol 200 (3) ◽  
pp. 685-690 ◽  
Author(s):  
K Grankvist
Keyword(s):  
Superoxide Dismutase ◽  
Hydroxyl Radicals ◽  
Metal Ion ◽  
Reduced Glutathione ◽  
Chemical Reactivity ◽  
Free System ◽  
A Cell ◽  
Radical Generation ◽  
Metal Ion Chelators

Chemiluminescence of luminol in a cell-free system was used to investigate the mechanism of alloxan-dependent free-radical generation. In the presence of alloxan and reduced glutathione (GSH), luminescence was greatly stimulated by FeSO4. Replacing GSH by oxidized glutathione or NAD(P)(H), or replacing FeSO4 by CuSO4, ZNSO4 or FeCl3, did not yield chemiluminescence. The chemiluminescence of a mixture of alloxan. GSH, FeSO4 and luminol was inhibited by catalase, superoxide dismutase, scavengers of hydroxyl radicals (sodium benzoate, n-butanol, D-mannitol, dimethyl sulphoxide) or metal-ion chelators (EDTA, diethylenetriaminepenta-acetic acid, diethyldithiocarbamate. desferroxamine), D-glucose, L-glucose, D-mannose, D-fructose, 3-O-methyl-D-glucose, NAD+, NADH, NADP+ or NADPH, but not by urea or enzymically inactive superoxide dismutase. The results support the hypothesis that the diabetogenic action of alloxan is mediated by hydroxyl radicals generated in an iron-catalysed reaction. Protection against alloxan in vivo depends both on the chemical reactivity of protector with radicals or radical-generating systems and on the stereospecific requirement of some strategic site in the B-cell.

Synergistic inhibition of the enzymatic activity of aminopeptidase N by divalent metal ion chelators

2006 ◽  
Vol 20 (6) ◽  
pp. 613-619 ◽  
Author(s):  
Patrick M.L. Vanderheyden ◽  
Heidi Demaegdt ◽  
Julie Swales ◽  
Pieter-Jan Lenaerts ◽  
Jean-Paul De Backer ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Metal Ion ◽  
Divalent Metal ◽  
Aminopeptidase N ◽  
Synergistic Inhibition ◽  
Divalent Metal Ion ◽  
Metal Ion Chelators

scholarly journals Characterization of a Highly Thermostable Alkaline Phosphatase from the Euryarchaeon Pyrococcus abyssi

2001 ◽  
Vol 67 (10) ◽  
pp. 4504-4511 ◽  
Author(s):  
Sébastien Zappa ◽  
Jean-Luc Rolland ◽  
Didier Flament ◽  
Yannick Gueguen ◽  
Joseph Boudrant ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Disulfide Bonds ◽  
Metal Ion ◽  
Divalent Cations ◽  
E Coli ◽  
Isolation And Characterization ◽  
Pyrococcus Abyssi ◽  
Increased Activity ◽  
Metal Ion Chelators

ABSTRACT This work reports the first isolation and characterization of an alkaline phosphatase (AP) from a hyperthermophilic archaeon. An AP gene from Pyrococcus abyssi, a euryarchaeon isolated from a deep-sea hydrothermal vent, was cloned and the enzyme expressed in Escherichia coli. Analysis of the sequence showed conservation of the active site and structural elements of theE. coli AP. The recombinant AP was purified and characterized. Monomeric and homodimeric active forms were detected, with a monomer molecular mass of 54 kDa. Apparent optimum pH and temperature were estimated at 11.0 and 70°C, respectively. Thus far,P. abyssi AP has been demonstrated to be the most thermostable AP, with half-lives at 100 and 105°C of 18 and 5 h, respectively. Enzyme activity was found to be dependent on divalent cations: metal ion chelators inhibited activity, whereas the addition of exogenous Mg(II), Zn(II), and Co(II) increased activity. The enzyme was inhibited by inorganic phosphate, but not by molybdate and vanadate. Strong inhibitory effects were observed in the presence of thiol-reducing agents, although cysteine residues of the P. abyssi AP were not found to be incorporated within intra- or interchain disulfide bonds. In addition,P. abyssi AP was demonstrated to dephosphorylate linear DNA fragments with dephosphorylation efficiencies of 93.8 and 84.1% with regard to cohesive and blunt ends, respectively.

scholarly journals Discovering New Medicines Targeting Helicases

2013 ◽  
Vol 18 (7) ◽  
pp. 761-781 ◽  
Author(s):  
William R. Shadrick ◽  
Jean Ndjomou ◽  
Rajesh Kolli ◽  
Sourav Mukherjee ◽  
Alicia M. Hanson ◽  
...  
Keyword(s):  
Herpes Simplex ◽  
Metal Ion ◽  
Drug Targets ◽  
Atp Hydrolysis ◽  
Nucleotide Analogues ◽  
Dead Box ◽  
Inhibitor Discovery ◽  
Polycyclic Aromatic ◽  
Simplex Virus ◽  
Metal Ion Chelators

Helicases are ubiquitous motor proteins that separate and/or rearrange nucleic acid duplexes in reactions fueled by adenosine triphosphate (ATP) hydrolysis. Helicases encoded by bacteria, viruses, and human cells are widely studied targets for new antiviral, antibiotic, and anticancer drugs. This review summarizes the biochemistry of frequently targeted helicases. These proteins include viral enzymes from herpes simplex virus, papillomaviruses, polyomaviruses, coronaviruses, the hepatitis C virus, and various flaviviruses. Bacterial targets examined include DnaB-like and RecBCD-like helicases. The human DEAD-box protein DDX3 is the cellular antiviral target discussed, and cellular anticancer drug targets discussed are the human RecQ-like helicases and eIF4A. We also review assays used for helicase inhibitor discovery and the most promising and common helicase inhibitor chemotypes, such as nucleotide analogues, polyphenyls, metal ion chelators, flavones, polycyclic aromatic polymers, coumarins, and various DNA binding pharmacophores. Also discussed are common complications encountered while searching for potent helicase inhibitors and possible solutions for these problems.

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