Search results for "phosphate"
showing 10 items of 1874 documents
CCDC 1490705: Experimental Crystal Structure Determination
2017
Related Article: Diego Rota Martir, Cristina Momblona, Antonio Pertegás, David B. Cordes, Alexandra M. Z. Slawin, Henk J. Bolink, and Eli Zysman-Colman|2016|ACS Applied Materials and Interfaces|8|33907|doi:10.1021/acsami.6b14050
Interaction of UO2(2+) with ATP in aqueous ionic media.
2005
Interaction of dioxouranium(VI) (uranyl) ion with ATP was studied by ligand/proton and metal/hydroxide displacement technique, at very low ionic strength and at I=0.15 mol L(-1), in aqueous Me4NCl and NaCl solutions, at t=25 degrees C. Measurements were carried out in the pH range 3-8.5, before the formation of precipitate. Computer analysis allowed us to find the quite stable species UO2(ATP)H2(0), UO2(ATP)H-, UO2(ATP)2-, UO2(ATP)2(6-), UO2(ATP)2H2(4-) and UO2(ATP)(OH)3- whose formation constants are (at I=0 mol L(-1)) logbeta(112)=18.21, logbeta(111)=14.70, logbeta(110)=9.14, logbeta(120)=12.84, logbeta(122)=24.82, and logbeta(11-1)=2.09, respectively. Different values were obtained in th…
Syntheses, X-ray structures, and physicochemical properties of phenoxo-bridged dinuclear nickel(II) complexes: kinetics of transesterification of 2-h…
2009
Four dinuclear nickel(II) complexes [Ni(II)(2)(L(1))(O(2)CMe)(2)(H(2)O)(2)][PF(6)].MeOH.3H(2)O (1), [Ni(II)(2)(L(1))(O(2)CMe)(2)(NCS)] (2), [Ni(II)(2)(L(2))(O(2)CMe)(2)(MeOH)(H(2)O)][ClO(4)] (3), and [Ni(II)(2)(L(2))(O(2)CMe)(2)(MeOH)(H(2)O)][BPh(4)].3MeOH.H(2)O (4) have been synthesized [HL(1): 2,6-bis[N-methyl-N-(2-pyridylethyl)amino]-4-methylphenol; HL(2): 2,6-bis[3-(pyridin-2-yl)pyrazol-1-ylmethyl]-4-methylphenol]. Complexes 1, 3, and 4 are new while complex 2 was reported previously by Fenton and co-workers (the structure of 2 was presented but no physicochemical properties of this complex were reported; in this work such studies have been completed). X-ray crystallographic analyses of…
Recovery of human fibroblasts from attack by the pore-forming alpha-toxin of Staphylococcus aureus.
1994
When applied at low concentrations (10 micrograms/ml), staphylococcal alpha-toxin generates a small channel in keratinocyte and lymphocyte membranes that permits selective transmembrane flux of monovalent ions. Here we show that a moderate concentration (1-50 micrograms/ml) of alpha-toxin similarly produces a small pore in membranes of human fibroblasts. This process leads to rapid leakage of K+ and to a drop in cellular ATP to 10-20% of normal levels in 2 h. In the presence of medium supplemented with serum and at pH 7.4, the cells are able to recover from toxin attack, so that normal levels of K+ and ATP are reached after 6-8 h at 37 degrees C. The repair process is dependent on the prese…
Subcytocidal attack by staphylococcal alpha-toxin activates NF-kappaB and induces interleukin-8 production.
2001
ABSTRACTFormation of transmembrane pores by staphylococcal alpha-toxin can provoke a spectrum of events depending on target cell species and toxin dose, and in certain cases, repair of the lesions has been observed. Here, we report that transcriptional processes are activated as a response of cells to low toxin doses. Exposure of monocytic (THP-1) or epithelial (ECV304) cells to 40 to 160 ng/ml alpha-toxin provoked a drop in cellular ATP level that was followed by secretion of substantial amounts of interleukin-8 (IL-8). Cells transfected with constructs comprising the proximal IL-8 promoter fused to luciferase or to green fluorescent protein cDNA exhibited enhanced reporter gene expression…
Extent of the influence of phosphate buffer and ionic liquids on the reduction of the silanol effect in a C18 stationary phase
2017
The presence of anionic free silanols in the silica-based stationary phases gives rise to broad and asymmetrical peaks when cationic basic compounds are chromatographed using hydro-organic mobile phases. The addition to the mobile phase of a reagent with ionic character prevents the access of analytes to the free silanols, improving the peak shape. The silanol activity can be affected by the buffer concentration and mobile phase pH, factors that are not always considered sufficiently in the literature. In this work, the chromatographic behaviour of three basic β-adrenoceptor antagonists (acebutolol, nadolol and timolol), using mobile phases containing acetonitrile, was examined at different…
Influence of inorganic pyrophosphate on the kinetics of muscle pyruvate kinase: a simple nonallosteric feedback model.
2002
Potassium pyrophosphate was used instead of ATP as a model ligand for magnesium cation for the study of effector influence on the kinetics of pyruvate kinase muscle isozyme M1. The pyruvate kinase activation by low concentration of pyrophosphate and inhibition by high concentration of pyrophosphate was considered to be the result of reversible reactions of magnesium cation with pyrophosphate, ADP, ATP, and PEP. The apparent Km and Vm or in some cases the pseudo-first order reaction rate constant (instead of Km and Vm) of pyruvate kinase at any given pyrophosphate concentration were analysed as a function of concentration of free magnesium cation and its complexes with all ligands present in…
A hypothetical model of the influence of inorganic phosphate on the kinetics of pyruvate kinase
2000
This paper presents a simple solution to the problem of approximating the calculated curve of reaction progress to the measured curve which is usually disturbed by initial oscillation of auxiliary lactate dehydrogenase (LDH) reaction. The experiments leading to the determination of the apparent Km for phosphoenolpyruvate (PEP) and Vm were performed. For precise estimation of kinetic parameters (Km and Vm) of the M1 isozyme of pyruvate kinase (PK), measured by coupling it to LDH reaction, the sequence of Michaelis‐Menten for pyruvate kinase and second-order kinetics for lactate dehydrogenase reaction as well as a non-zero initial concentration of lactate was assumed. The functions of apparen…
Phytoelectrochemical analysis ofZanthoxylum chiloperone
2016
Introduction An innovative application of the voltammetry of microparticles methodology to characterize the phytochemical composition of extracts of different parts of Zanthoxylum chiloperone var. angustifolium Engl. is described. Objective Characterize the phytochemical composition of extracts of different parts of plants by electrochemical methodologies. Methods The voltammetry of microparticles methodology was applied to alcoholic extracts from leaves, seeds, fruits, roots and stem bark of Zanthoxylum chiloperone. Results In contact with aqueous phosphate buffer, characteristic cathodic signals of its main natural products (canthin-6-one, 5-methoxycanthin-6-one and trans-avicennol) were …
Solid‐State Anion–Guest Encapsulation by Metallosupramolecular Capsules Made from Two Tetranuclear Copper(II) Complexes
2007
A new cationic tetranuclear copper(II) complex self-assembles from one 1,3-phenylenebis(oxamato) (mpba) bridging ligand and four CuII ions partially blocked with N,N,N′,N′-tetramethylethylenediamine (tmen) terminal ligands. In the solid state, two of these tetracopper(II) oxamato complexes of bowl-like shape and helical conformation then serve as a building block for the generation of either hetero- (MP) or homochiral (MM/PP) dimeric capsules depending on the nature of the encapsulated anion guest, perchlorate or hexafluorophosphate. The overall magnetic behaviour of these metallosupramolecular capsules does not depend on the nature of the encapsulated anion guest, but it is consistent with…