A new contribution to the determination of the complex equilibria of oxidised glutathione with proton and copper(II) in aqueous solution

Blais, Marie-José; Berthon, Guy

doi:10.1039/dt9820001803

Cited by 25 publications

(10 citation statements)

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“…In papers [4][5][6][7][8] divergences in estimation of stability constants of identical complexes are so evident that they cannot be attributed to different experimental conditions. Electronic and electron paramagnetic resonance (EPR) spectra parameters of the mentioned individual forms were not reported.…”

Section: Introductionmentioning

confidence: 94%

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Structure, stability, and ligand exchange of copper(II) complexes with oxidized glutathione

Штырлин

Zyavkina

Ilakin

et al. 2005

Journal of Inorganic Biochemistry

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Section: Introductionmentioning

confidence: 94%

“…The literature data [4][5][6][7][8] on thermodynamics of complex formation between copper(II) and GSSG are [8] were considered as significant forms. In papers [4][5][6][7][8] divergences in estimation of stability constants of identical complexes are so evident that they cannot be attributed to different experimental conditions.…”

Section: Introductionmentioning

confidence: 99%

Structure, stability, and ligand exchange of copper(II) complexes with oxidized glutathione

Штырлин

Zyavkina

Ilakin

et al. 2005

Journal of Inorganic Biochemistry

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“…Steric interaction between GSSG molecules has previously been inferred from calculations based on potentiometric data (Micheloni et al 1978), but so far no experimental evidence allows the distinction between the two dimer models in Scheme 1. To account for simulations of potentiometric titrations, the existence of an intermediate GSSG dimer with only one Cu2+ bound has been postulated (Micheloni et al 1978, Abello et al 1980, but this result was later ascribed to a computer program artifact (Blais & Berthon 1982).…”

Section: The Question Of the Second Binding Sitementioning

confidence: 99%

Copper-glutathione complexes under physiological conditions: structures in solution different from the solid state coordination

Steinkühler

Weser

et al. 1996

Biometals

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The physiologically important copper complexes of oxidized glutathione have been examined by electron spin resonance (ESR) spectroscopy in aqueous solution at neutral pH. Low temperature measurements show that the Cu(ll) binding site in oxidized glutathione has the same ligand arrangement as in the copper complexes of S-methylglutathione, glutamine, glutamate and glycine. The site is composed of the amino nitrogens and the carboxyl oxygens of two ?-glutamyl residues; there is no interaction with amide nitrogens, the sulphur bond or the glycyl carboxyl groups. At high metal to ligand ratios a binuclear species exists, in which each Cu(II) binds only to one 7-glutamyl residue. The previously reported forbidden transition detected at g = 4 is due to non-specific aggregation and not to spin coupling of intramolecular sites. Liquid solution ESR spectra show the Cu(II)-glutathione complex has a lower mobility than the corresponding Cu(II)-S-methylglutathione species. From the degree of spectral anisotropy the complex with glutathione is calculated to exist as a dimer. These results demonstrate that the physiologically relevant complex between copper and oxidized glutathione in solution is completely different from the known solid state structure determined by crystallography.

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“…Our usual optimization/simulation two stage approach [13,43] was used. For each system, the stoicheiometries of the possible complexes likely to account for the experimental data were derived from the shape of the relevant formation curves.…”

Section: Calculation Proceduresmentioning

confidence: 99%

Metal ion-tetracycline interactions in biological fluids. Part 5. Formation of zinc complexes with tetracycline and some of its derivatives and assessment of their biological significance

1985

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A series of studies was previously devoted to the dependence of the bioavailability of various tetracyclines on their coordination with calcium and magnesium ions. Several clinical investigations have also shown zinc to interfere with the gastrointestinal absorption of the drug in humans. On the other hand, the administration of tetracycline to rats was reported to result in the increase of the elimination rate of zinc, which could originate in zinc-tetracycline interactions in blood plasma. Formation constants for zinc complexes with tetracycline, oxytetracycline, doxycycline, minocycline, chlortetracycline and demethylchlortetracycline were thus determined at 37 degrees C in NaCl 0.15 mol. dm-3 aqueous medium. Computer simulations were then carried out to investigate the drug influence on the distribution of the low-molecular-weight fraction of zinc in human blood plasma. Zinc-tetracycline interactions in the gastrointestinal fluid were also simulated, using clinical data relative to fasting subjects as taken from the literature. No significant effect can be expected from tetracyclines on the distribution of zinc in plasma at the usual therapeutic levels. However, zinc-tetracycline interactions have been found to be determining factors for the bioavailabilities of the metal as well as of the antibiotic in the gastrointestinal fluid.

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A new contribution to the determination of the complex equilibria of oxidised glutathione with proton and copper(II) in aqueous solution

Cited by 25 publications

References 1 publication

Structure, stability, and ligand exchange of copper(II) complexes with oxidized glutathione

Structure, stability, and ligand exchange of copper(II) complexes with oxidized glutathione

Copper-glutathione complexes under physiological conditions: structures in solution different from the solid state coordination

Metal ion-tetracycline interactions in biological fluids. Part 5. Formation of zinc complexes with tetracycline and some of its derivatives and assessment of their biological significance

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