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Evaluation of [Co(gly)3]- as a 35Cl- NMR shift reagent for cellular studies
- Source :
- Repositório Científico de Acesso Aberto de Portugal, Repositório Científico de Acesso Aberto de Portugal (RCAAP), instacron:RCAAP
- Publication Year :
- 2003
-
Abstract
- We studied the efficacy of the tris-glycinatocobaltate(II) complex ([Co(gly)(3)](-)) as a shift reagent (SR) for chloride by (35)Cl NMR spectroscopy and compared to that of Co(2+)((aq)). Due to the relatively low thermodynamic stability of [Co(gly)(3)](-), a 1:3 Co(II)/gly stoichiometric solution at physiological pH is approximately a 2:1 mixture of [Co(gly)(2)(H(2)O)(2)] and [Co(gly)(H(2)O)(4)](+). This SR was found to be stable up to higher pH values than Co(2+)((aq)), better preventing Co(OH)(2) formation at alkaline pH. No significant differences in the (35)Cl(-) NMR chemical shift induced by Co(II)/gly or Co(2+)((aq)) were observed in the presence of physiological concentrations of either Ca(2+) or Mg(2+), or of either Na(+) or K(+). Although Co(2+)((aq)) was almost twice as effective as Co(II)/gly in shifting the (35)Cl(-) NMR resonance at the same high rho ([SR]/[Cl(-)]) value and low ionic strength, Co(2+)((aq)) showed a significant decrease (p < 0.05) in the (35)Cl(-) chemical shift at higher ionic strength. Line widths at half-height were significantly (p < 0.05) less for Co(II)/gly than for Co(2+)((aq)) at rho values in the range 0.066-0.40. Intracellular chloride was clearly detectable by (35)Cl NMR spectroscopy in human skin fibroblast cells suspended in medium containing 40 mM Co(II)/gly SR. We determined that, although Co(2+)((aq)) provides a larger shift than Co(II)/gly at the same rho value, there are significant advantages for using Co(II)/gly, such as pH stability, ionic strength independent chemical shifts, narrow (35)Cl(-) NMR resonances, and reduced cellular toxicity, as a SR in biological systems.
- Subjects :
- animal structures
Magnetic Resonance Spectroscopy
Stereochemistry
Glycine
Medicinal chemistry
Chloride
Inorganic Chemistry
Chlorides
Isotopes
medicine
Humans
Physical and Theoretical Chemistry
Cells, Cultured
integumentary system
Chemistry
Chemical shift
Resonance
Nuclear magnetic resonance spectroscopy
Cobalt
Fibroblasts
Hydrogen-Ion Concentration
Ionic strength
Reagent
Thermodynamics
Chemical stability
Indicators and Reagents
Stoichiometry
medicine.drug
Subjects
Details
- ISSN :
- 00201669
- Volume :
- 42
- Issue :
- 8
- Database :
- OpenAIRE
- Journal :
- Inorganic chemistry
- Accession number :
- edsair.doi.dedup.....1aa63355548ffc5fcb2654c994db8bbd