Effect of Ionic Strength, Aquo-Organic Solvents, and Temperature on the Stabilities of <i>N</i>-[Tris(hydroxymethyl)methyl]glycine + Metal Complexes

El‐Roudi, Omar M.; Abdel‐Latif, Samir A.

doi:10.1021/je030228c

Cited by 11 publications

(4 citation statements)

References 26 publications

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“…Potentiometry experiments have provided reliable protonation constants and formation constants for many binary metal−ion (amino acid) complexes in aqueous solutions of 0.1 M or 0.15 M (physiological) ionic strength at 293.15 K, 298.15 K, or 310.15 K. , KNO 3 or NaClO 4 is most often employed as the background electrolyte. In certain cases, coordination enthalpies and entropies are reported at either 298.15 K or 310.15 K. − The decomposition of a formation constant into its enthalpic and entropic contributions is of fundamental importance to understanding the factors that influence the coordination reaction and the stability of the complex. These factors may include solvation, steric, and electronic effects.…”

Section: Introductionmentioning

confidence: 99%

Formation Constants and Coordination Thermodynamics for Binary and Ternary Complexes of Copper(II), l-Hydroxyproline, and an Amino Acid Enantiomer

Sanaie

Haynes

2005

J. Chem. Eng. Data

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While a rich database is available at or near room temperature (288.15 to 298.15 K) defining the chemical equilibria of solutions containing the copper(II) ion and an amino acid, data describing the temperature dependence of reaction thermodynamics for these systems remain scarce. In addition, data defining enthalpy, entropy, and heat capacity changes for the formation of mixed amino acid chelate complexes are extremely limited, hindering our understanding of the driving forces for complex formation and stabilization. Here, protonation constants and concentration-based equilibrium constants for Cu(II)amino acid complexes are reported from 288.15 to 348.15 K for leucine, valine, proline, phenylalanine, and hydroxyproline in aqueous solutions containing 0.1 M KNO 3 . The logarithmic (ln) values of the protonation and binary stepwise concentration equilibrium constants (K i ) for each amino acid ligand are found to be linearly dependent on the inverse of temperature, indicating negligible change in heat capacity for each of these protonation and complexation reactions. However, ln(K i ) data for ternary complexes formed between Cu(II), L-hydroxyproline, and any one of the other amino acid enantiomers show a nonlinear dependence on inverse temperature, indicating a negative change in heat capacity. Enthalpy and entropy changes for ternary complex formation are therefore temperature-dependent quantities. Our thermodynamic data, when combined with statistical analysis of reaction stoichiometry, reveal that ternary Cu(II)(D′ or L′)(L-hydroxyproline) complexes are consistently hyperstable as compared to their parent bisbinary complexes at all solution temperatures studied.

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Section: Introductionmentioning

confidence: 99%

Formation Constants and Coordination Thermodynamics for Binary and Ternary Complexes of Copper(II), l-Hydroxyproline, and an Amino Acid Enantiomer

Sanaie

Haynes

2005

J. Chem. Eng. Data

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“…; Aydin and Yirikogullari ) or tricine (logK CuL =7.8) (Good et al . ; El‐Roudi and Abdel‐Latif ), it seems justified to propose that our observations are related to the formation of stable kainate‐Cu 2+ complexes. Minor differences between the effects of KA and tricine we observed could then be accounted for by differences in their metal ion binding properties and/or concentration.…”

Section: Discussionmentioning

confidence: 78%

Reciprocal modulation of Ca_v2.3 voltage‐gated calcium channels by copper(II) ions and kainic acid

Neumaier

Akhtar-Schäfer

Lüke

et al. 2018

Journal of Neurochemistry

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Kainic acid (KA) is a potent agonist at non-N-methyl-D-aspartate (non-NMDA) ionotropic glutamate receptors and commonly used to induce seizures and excitotoxicity in animal models of human temporal lobe epilepsy. Among other factors, Ca 2.3 voltage-gated calcium channels have been implicated in the pathogenesis of KA-induced seizures. At physiologically relevant concentrations, endogenous trace metal ions (Cu , Zn ) occupy an allosteric binding site on the domain I gating module of these channels and interfere with voltage-dependent gating. Using whole-cell patch-clamp recordings in human embryonic kidney (HEK-293) cells stably transfected with human Ca 2.3d and β -subunits, we identified a novel, glutamate receptor-independent mechanism by which KA can potently sensitize these channels. Our findings demonstrate that KA releases these channels from the tonic inhibition exerted by low nanomolar concentrations of Cu and produces a hyperpolarizing shift in channel voltage-dependence by about 10 mV, thereby reconciling the effects of Cu chelation with tricine. When tricine was used as a surrogate to study the receptor-independent action of KA in electroretinographic recordings from the isolated bovine retina, it selectively suppressed a late b-wave component, which we have previously shown to be enhanced by genetic or pharmacological ablation of Ca 2.3 channels. Although the pathophysiological relevance remains to be firmly established, we speculate that reversal of Cu -induced allosteric suppression, presumably via formation of stable kainate-Cu complexes, could contribute to the receptor-mediated excitatory effects of KA. In addition, we discuss experimental implications for the use of KA in vitro, with particular emphasis on the seemingly high incidence of trace metal contamination in common physiological solutions.

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“…So, the solvent system or medium for the metal ion interaction is critical for optimizing the stabilities of metal ligand complexes. The role of solvent on metal-ligand interactions will provide a more comprehensive understanding of solvent dependent nature of metal-ligand interactions and ligand-ligand interactions in binary and ternary systems in solution [96][97]. Specifically, solvent plays an important role in ligand-ligand interactions in ternary complexes and therefore, it is useful in the identification of intramolecular interactions in ternary complexes [98][99][100][101].…”

Section: Effect Of Solvent On the Stabilities Of Metal Ligand Complexmentioning

confidence: 99%

Effect of Mixed Solvent System on Intramolecular Interactions of Metal Mediated Ternary Complexes of Beta-Hydroxy Ketone Derivatives and Benzotriazole Derivatives in Solution.

Ramu¹,

Marupati²

2017

IJAR

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The stabilities of ternary complexes of metal ions (copper, nickel, zinc and cobalt) with beta-hydroxy ketone(BHK) derivatives and benzotriazole(BTAZ) derivatives in various mixed solvent systems (Water+Dioxane) medium in 0.1 M KNO3 ionic strength at 25 0 C using pH metric titration method have been established. The data reveal that the copper forms more stable complexes, which is followed by zinc and Ni complexes with these ligands. Cobalt form less stable complexes with these ligands. The stabilities of these complexes are further quantified with Δ log K values, intra-molecular equilibrium constants and percentage of stacking interaction in the ternary systems. The observed positive Δ log K values suggest that the flexible side chain alkyl moiety (ethyl group, butyl group) or aromatic moiety (phenyl group) in BHK ligand overlaps with the fixed aromatic moiety of BTAZ ligand in the ternary complex, which results in the …………………………………………………………………………………………………….... Introduction:-A metal ion interactions with various ligands is an extremely diversified field [1][2][3][4][5][6][7][8][9][10][11], because the interaction as well as the resulting complex can have different applications in the biological field [12][13][14][15][16][17][18][19][20][21], development of luminescent materials, color stabilizing agents for toners in color photography, catalysts, therapeutic advantage [22][23][24][25][26][27][28][29][30][31][32][33][34], in the electronic display devices [35][36][37][38][39][40][41][42][43][44][45][46][47] or fluorescent probes [48][49][50][51][52][53][54][55][56][57][58] and can also be used in the resin technology [59][60][61][62][63][64][65]. In all these cases, the utility of metal-ligand complex is directly related to the stability of the complex which is a tunable parameter.The ligand can be a biomolecule [66][67][68][69][70] or a complexing agent [71][72][73][74][75] or simply scientifically a designed compound [76][77][78][79][80]. Both the metal ion interactions with the ligands and the metal-ligand complexes have been

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Effect of Ionic Strength, Aquo-Organic Solvents, and Temperature on the Stabilities of N-[Tris(hydroxymethyl)methyl]glycine + Metal Complexes

Abstract: The stability constants of complexes of N- [(tris-hydroxymethyl)methyl]glycine (Tricine) with the transition metal ions Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ were studied potentiometrically in the presence of (0.02, 0.05, 0.10, and 0.15) mol dm -3

Cited by 11 publications

References 26 publications

Formation Constants and Coordination Thermodynamics for Binary and Ternary Complexes of Copper(II), l-Hydroxyproline, and an Amino Acid Enantiomer

Formation Constants and Coordination Thermodynamics for Binary and Ternary Complexes of Copper(II), l-Hydroxyproline, and an Amino Acid Enantiomer

Reciprocal modulation of Ca_v2.3 voltage‐gated calcium channels by copper(II) ions and kainic acid

Effect of Mixed Solvent System on Intramolecular Interactions of Metal Mediated Ternary Complexes of Beta-Hydroxy Ketone Derivatives and Benzotriazole Derivatives in Solution.

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Effect of Ionic Strength, Aquo-Organic Solvents, and Temperature on the Stabilities of N-[Tris(hydroxymethyl)methyl]glycine + Metal Complexes

Abstract: The stability constants of complexes of N- [(tris-hydroxymethyl)methyl]glycine (Tricine) with the transition metal ions Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ were studied potentiometrically in the presence of (0.02, 0.05, 0.10, and 0.15) mol dm -3

Cited by 11 publications

References 26 publications

Formation Constants and Coordination Thermodynamics for Binary and Ternary Complexes of Copper(II), l-Hydroxyproline, and an Amino Acid Enantiomer

Formation Constants and Coordination Thermodynamics for Binary and Ternary Complexes of Copper(II), l-Hydroxyproline, and an Amino Acid Enantiomer

Reciprocal modulation of Cav2.3 voltage‐gated calcium channels by copper(II) ions and kainic acid

Effect of Mixed Solvent System on Intramolecular Interactions of Metal Mediated Ternary Complexes of Beta-Hydroxy Ketone Derivatives and Benzotriazole Derivatives in Solution.

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Reciprocal modulation of Ca_v2.3 voltage‐gated calcium channels by copper(II) ions and kainic acid