Calcium

Peterlik, Meinrad; Stoeppler, M.

doi:10.1002/9783527619634.ch23h

Cited by 3 publications

(5 citation statements)

References 90 publications

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“…The effective free calcium concentration in the cell is in the range 10 –6 to 10 –8 mol kg –1 , and in the sarcoplasme it is close to 10 –3 mol kg –1 . Only free calcium results effective in the regulation of the cellular processes . The total extracellular calcium is 2.5 mmol kg –1 ; ∼50% is present as free ion, 40% is complexed by plasma proteins, and 10% is bound to citrate and phosphate .…”

Section: Introductionmentioning

confidence: 99%

“…Only free calcium results effective in the regulation of the cellular processes . The total extracellular calcium is 2.5 mmol kg –1 ; ∼50% is present as free ion, 40% is complexed by plasma proteins, and 10% is bound to citrate and phosphate . The main donor groups to the calcium cation from proteins are carbonyl and carboxylate centers .…”

Section: Introductionmentioning

confidence: 99%

“…The main donor groups to the calcium cation from proteins are carbonyl and carboxylate centers . The rigid control of plasma free calcium is very important because even small differences in concentration can cause significant changes in both intracellular free calcium as well as the skeletal site, with unavoidable consequences on bone health. , …”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca²⁺in Aqueous Solution at Different Ionic Strengths and Temperatures

et al. 2019

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A potentiometric and UV spectrophotometric study on Ca 2+ −ampicillin and −amoxicillin systems in NaCl aqueous solution is reported. The potentiometric investigation was carried out at different ionic strengths, I = (0.15 to 1) mol kg −1 , and temperatures, T = (288.15 to 310.15) K. The most reliable speciation models include two species, namely, CaLH and CaL for the Ca 2+ −ampicillin system and CaLH 2 and CaLH for the Ca 2+ − amoxicillin system. The spectrophotometric results obtained for both of the systems are fully consistent with potentiometric ones, confirming the formation as well as the stability of the complex species. The dependence of formation constants of the species on ionic strength over the range I = (0.15 to 1) mol kg −1 in NaCl and on temperature over the range T = (288.15 to 310.15) K is also reported. pL 0.5 empirical parameter (i.e., the concentration of ligand required to bind 50% of the metal cation present in the trace) was employed to evaluate the ability of both of the ligands to sequester Ca 2+ under different conditions of pH, ionic strength, and temperature. For example, pL 0.5 = 1.82 and 2.88, for ampicillin and amoxicillin, respectively, were obtained under physiological conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca²⁺in Aqueous Solution at Different Ionic Strengths and Temperatures

et al. 2019

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“…Calcium represents the fifth most abundant metal in the environment and in the human body. It is essential for the lives of animals and plants and present in the skeleton of animals, in teeth, in coral, and in many soils . In addition to its relevant biological role, calcium is widely employed in different industrial processes.…”

Section: Introductionmentioning

confidence: 99%

“…The calcium content of seawater is high, on average in the oceans at about 390 mg kg –1 . Rivers are characterized by quite different calcium contents, depending upon their geological origin …”

Section: Introductionmentioning

confidence: 99%

Phosphonic Derivatives of Nitrilotriacetic Acid as Sequestering Agents for Ca²⁺ in Aqueous Solution: A Speciation Study for Application in Natural Waters

Cordaro

Foti

Giacobello

et al. 2019

ACS Earth Space Chem.

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A speciation study on the interaction between Ca 2+ and three phosphonic derivative ligands of nitrilotriacetic acid in aqueous solution is reported. The ligands under study are N-(phosphonomethyl)iminodiacetic acid (NTAP), N,Nbis(phosphonomethyl)glycine (NTA2P), and nitrilotris(methylenephosphonic acid) (NTA3P). The most likely speciation models obtained from the elaboration of the potentiometric data include only species with a 1:1 metal/ligand ratio. In detail, two species, CaLH and CaL, for the NTAP ligand and three species, CaLH 2 , CaLH, and CaL, for the NTA2P and NTA3P ligands were observed. The potentiometric measurements were carried out at different ionic strengths (0.15 ≤ I ≤ 1 mol L −1 , in NaCl) and different temperatures (288.15 ≤ T ≤ 318.15 K, at I = 0.15 mol L −1 ). The dependence of formation constants of the complex species upon the temperature and ionic strength was also determined, and the enthalpy change values were calculated. The 1 H nuclear magnetic resonance spectra on metal−ligand solutions, registered as a function of pH, have underlined a characteristic complexing behavior of each ligand toward Ca 2+ . The spectra of the ligand and metal−ligand solutions are fully consistent with potentiometric results for all of the systems. These data confirm the complex formation as well as speciation models and stability of the species. The sequestering ability of NTAP, NTA2P, and NTA3P toward Ca 2+ was evaluated under different conditions of the temperature and pH, typical of natural waters.

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Ca2+ Complexation With Relevant Bioligands in Aqueous Solution: A Speciation Study With Implications for Biological Fluids

et al. 2021

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A speciation study on the interaction between Ca2+ and ligands of biological interest in aqueous solution is reported. The ligands under study are l-cysteine (Cys), d-penicillamine (PSH), reduced glutathione (GSH), and oxidized glutathione (GSSG). From the elaboration of the potentiometric experimental data the most likely speciation patterns obtained are characterized by only protonated species with a 1:1 metal to ligand ratio. In detail, two species, CaLH2 and CaLH, for systems containing Cys, PSH, and GSH, and five species, CaLH5, CaLH4, CaLH3, CaLH2, and CaLH, for system containing GSSG, were observed. The potentiometric titrations were performed at different temperatures (15 ≤ t/°C ≤ 37, at I = 0.15 mol L−1). The enthalpy and entropy change values were calculated for all systems, and the dependence of the formation constants of the complex species on the temperature was evaluated. 1H NMR spectroscopy, MALDI mass spectrometry, and tandem mass spectrometry (MS/MS) investigations on Ca2+-ligand solutions were also employed, confirming the interactions and underlining characteristic complexing behaviors of Cys, PSH, GSH, and GSSG toward Ca2+. The results of the analysis of 1H NMR experimental data are in full agreement with potentiometric ones in terms of speciation models and stability constants of the species. MALDI mass spectrometry and tandem mass spectrometry (MS/MS) analyses confirm the formation of Ca2+-L complex species and elucidate the mechanism of interaction. On the basis of speciation models, simulations of species formation under conditions of some biological fluids were reported. The sequestering ability of Cys, PSH, GSH, and GSSG toward Ca2+ was evaluated under different conditions of pH and temperature and under physiological condition.

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Calcium

Cited by 3 publications

References 90 publications

Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca²⁺in Aqueous Solution at Different Ionic Strengths and Temperatures

Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca²⁺in Aqueous Solution at Different Ionic Strengths and Temperatures

Phosphonic Derivatives of Nitrilotriacetic Acid as Sequestering Agents for Ca²⁺ in Aqueous Solution: A Speciation Study for Application in Natural Waters

Ca2+ Complexation With Relevant Bioligands in Aqueous Solution: A Speciation Study With Implications for Biological Fluids

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Calcium

Cited by 3 publications

References 90 publications

Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca2+in Aqueous Solution at Different Ionic Strengths and Temperatures

Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca2+in Aqueous Solution at Different Ionic Strengths and Temperatures

Phosphonic Derivatives of Nitrilotriacetic Acid as Sequestering Agents for Ca2+ in Aqueous Solution: A Speciation Study for Application in Natural Waters

Ca2+ Complexation With Relevant Bioligands in Aqueous Solution: A Speciation Study With Implications for Biological Fluids

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Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca²⁺in Aqueous Solution at Different Ionic Strengths and Temperatures

Thermodynamic Study on the Interaction of Ampicillin and Amoxicillin with Ca²⁺in Aqueous Solution at Different Ionic Strengths and Temperatures

Phosphonic Derivatives of Nitrilotriacetic Acid as Sequestering Agents for Ca²⁺ in Aqueous Solution: A Speciation Study for Application in Natural Waters