scholarly journals The Influence of pH on Complexation Process of Copper(II) Phosphoethanolamine to Pyrimidine Nucleosides

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4309
Author(s):  
Malwina Gabryel-Skrodzka ◽  
Martyna Nowak ◽  
Klaudia Stachowiak ◽  
Michal Zabiszak ◽  
Kazuma Ogawa ◽  
...  
Keyword(s):  
Equilibrium Constants ◽  
Computer Calculation ◽  
Biological Applications ◽  
Pyrimidine Nucleosides ◽  
Species Formation ◽  
Overall Stability ◽  
Influence Of Ph ◽  
Mode Of Coordination ◽  
Phosphate Groups ◽  
Complexation Process

The influence of pH on the complex formation of phosphoethanolamine and pyrimidine nucleosides (uridine, cytidine and thymidine) with copper(II) ions was studied. All investigations were performed in aqueous solution. The overall stability constants of the complexes and non-covalent compounds were obtained using the potentiometric method with computer calculation of the data. Moreover, equilibrium constants of the reaction were determined. The mode of coordination was obtained using spectroscopic methods. Analysis of the potentiometric and spectroscopic data confirmed the involvement and effectiveness of phosphate groups in species formation as well as the influence of pH on the mode of coordination of the investigated biomaterials. In the next step, studied complexes will be applied as potential biomaterials with biological applications.

scholarly journals Coordination Reactions and Noncovalent Interactions of Polyamines with Nucleotides in Binary Systems and with Nucleotides and Copper(II) Ion in Ternary Systems

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Lechoslaw Lomozik ◽  
Anna Gasowska ◽  
Grzegorz Krzysko ◽  
Romualda Bregier-Jarzebowska
Keyword(s):  
Binary Systems ◽  
Noncovalent Interactions ◽  
Ternary Systems ◽  
Coordination Sites ◽  
Protonated Amine ◽  
Overall Stability ◽  
Methylene Groups ◽  
Amine Groups ◽  
Mode Of Coordination ◽  
Phosphate Groups

Interactions of nucleotides (AMP, CMP) and 1,2-diaminopropane (tn-1) or 2-methyl-1,2-diaminopropane (tn-2) in metal-free systems as well as in the systems including copper(II) ions were studied. The composition and overall stability constants of the complexes formed were determined by the potentiometric method, whereas the interaction centres and coordination sites were identified by spectroscopic methods. It was found that phosphate groups of nucleotides and the protonated amine groups of polyamines are the centres of interaction. The differences in the interactions with the polyamines which act as models of biogenic amines are impacted by the presence of lateral chains (methylene groups) in tn-1 and tn-2. In the ternary systems with Cu(II) ions, the heteroligand complexes are mainly of the ML⋯L’ type, in which the protonated polyamine is engaged in noncovalent interactions with the anchoring Cu(II)-nucleotide complex. The complexes formed in the Cu/NMP)/tn-1 system are more stable than those formed in the system with tn-2. The mode of coordination in the complex is realised mainly through the phosphate groups of the nucleotide with involvement of the endocyclic nitrogen atoms in a manner which depends upon the steric conditions and in particular on the number of the methylene groups in the polyamine molecule.

scholarly journals Thermodynamic and Spectroscopic Studies of the Complexes Formed in Tartaric Acid and Lanthanide(III) Ions Binary Systems

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1121 ◽  
Author(s):  
Michal Zabiszak ◽  
Martyna Nowak ◽  
Zbigniew Hnatejko ◽  
Jakub Grajewski ◽  
Kazuma Ogawa ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Stability Constants ◽  
Binary Systems ◽  
Equilibrium Constants ◽  
Spectroscopic Studies ◽  
Luminescence Spectroscopy ◽  
Binary Complexes ◽  
Overall Stability ◽  
The Stability

Binary complexes of tartaric acid with lanthanide(III) ions were investigated. The studies have been performed in aqueous solution using the potentiometric method with computer analysis of the data for detection of the complexes set, determination of the stability constants of these compounds. The mode of the coordination of complexes found was determined using spectroscopy, which shows: Infrared, circular dichroism, ultraviolet, visible as well as luminescence spectroscopy. The overall stability constants of the complexes as well as the equilibrium constants of the reaction were determined. Analysis of the equilibrium constants of the reactions and spectroscopic data allowed the effectiveness of the carboxyl groups in the process of complex formation.

scholarly journals Studies of Binary Complexes of Tripodal Ligandcis,cis-1,3,5-tris(methylamino)cyclohexane with Cr(III) and Fe(III)

2005 ◽  
Vol 2 (1) ◽  
pp. 52-57
Author(s):  
S. Esakki Muthu ◽  
Suban K. Sahoo ◽  
Minati Baral ◽  
B. K. Kanungo
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Molecular Mechanics ◽  
Stability Constants ◽  
Potentiometric Method ◽  
Molecular Mechanics Calculations ◽  
Tripodal Ligand ◽  
Binary Complexes ◽  
Overall Stability ◽  
Mode Of Coordination

The formation of binary complexes of Cr(III) and Fe(III) with a tripodal ligandcis,cis-1,3,5-tris(methylamino)cyclohexane (tmach) (L) has been investigated in solution. The overall stability constants oftmachwith Cr(III) and Fe(III) were determined by potentiometric method at an ionic strength of 0.1 M NaClO4at 25±1°C in aqueous medium. The formation of species like MLH25+, MLH4+, ML3+, ML(OH)2+and ML(OH)3were observed. Fe(III) was found to form more stable complexes than Cr(III). Molecular mechanics calculations were performed to explain the mode of coordination in solution.

scholarly journals Acid-base equilibria of 2,4-diiodo-6-methylphenylcarbamoylmethyl iminodiacetic acid and its labeling with technetium-99m

2006 ◽  
Vol 71 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Jasmina Brboric ◽  
Mirjana Jovanovic ◽  
Gordana Popovic ◽  
Vera Kapetanovic ◽  
Sote Vladimirov
Keyword(s):  
Ionic Strength ◽  
Radiochemical Purity ◽  
Equilibrium Constants ◽  
Iminodiacetic Acid ◽  
Carboxylic Group ◽  
Acid Base ◽  
Acidity Constants ◽  
Technetium 99M ◽  
Ph Range ◽  
Influence Of Ph

The acid-base equilibria of a novel hepatobiliary imaging agent, 2,4-diiodo-6-methylphenylcarbamoylmethyl iminodiacetic acid (DIIODIDA) were studied. The potentiometrically determined acidity constants of the second carboxylic group, amino and amide groups were pK2 = 2.52 ? 0.02; pK3 = 5.86 ? 0.06 and pK4 = 10.9 ? 0.1. The determinations were performed at 25 ?C and an ionic strength of 0.1 mol/dm3 (NaCl). The acidity constants (pK1 = 1.3 ? 0.4) corresponding to the first carboxylic group was determined indirectly, on the basis of equilibrium constants obtained in a heterogeneous system, at 25 ?C and an ionic strength 1 mol/dm3 (HCl, NaCl). DIIODIDA was labeled with technetium-99m, and the influence of pH on the yield of labeling was investigated. It was found that labeling within the pH range from 5.5 to 6.5 provided a radiopharmaceutical of high radiochemical purity (>98 %).

scholarly journals The Effect of Stereochemistry on Sodium Ion Complexation in Nucleoside-Metallacarborane Conjugates

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Agnieszka B. Olejniczak ◽  
Jan Milecki ◽  
Grzegorz Schroeder
Keyword(s):  
Complex Formation ◽  
Alkali Metals ◽  
Equilibrium Constants ◽  
Biological Properties ◽  
Biological Evaluation ◽  
Sodium Ion ◽  
Pyrimidine Nucleosides ◽  
Esi Ms ◽  
Complexing Properties ◽  
Physicochemical And Biological Properties

Conjugates of purine and pyrimidine nucleosides: thymidine and -deoxyguanosine with cobalt-metallacarborane were studied for their sodium ion complexing properties. Formation of stable complexes of 1 : 1 stoichiometry was proved by ESI MS spectroscopy and NMR. Equilibrium constants and energies of complex formation were calculated. Complexation of alkali-metals by nucleoside-metallacarborane conjugates may affect the physicochemical and biological properties of the conjugates and should be taken into consideration during biological evaluation of these types of modifications.

Equilibrium Constants for 2,3-Dihydroxypyridine and its Complex with Iron(III) in 1 M Hydrochloric Acid

1972 ◽  
Vol 50 (11) ◽  
pp. 1649-1654 ◽  
Author(s):  
K. E. Curtis ◽  
G. F. Atkinson
Keyword(s):  
Hydrochloric Acid ◽  
Stability Constants ◽  
Equilibrium Constants ◽  
Acidity Constants ◽  
Overall Stability

Improved values for two acidity constants of 2,3-dihydroxypyridine have been computed using program PITMAP. The composition of the complex with iron(III) and its conditional and overall stability constants in 1 M hydrochloric acid have been evaluated.

scholarly journals Biocatalytic Synthesis of 2-Seleno Pyrimidine Nucleosides via Transglycosylation

2020 ◽  
Author(s):  
Katja Hellendahl ◽  
Felix Kaspar ◽  
Xinrui Zhou ◽  
Zhaoyi Yang ◽  
Zhen Huang ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Equilibrium Constants ◽  
Aqueous Media ◽  
Scale Up ◽  
Modified Nucleosides ◽  
Pyrimidine Nucleosides ◽  
Hypoxic Conditions ◽  
And Function ◽  
Nucleoside Phosphorylases ◽  
Optimized Conditions

Selenium-modified nucleosides are powerful tools to study the structure and function of nucleic acids and their protein interactions. The wide-spread application of 2-seleno pyrimidine nucleosides is currently limited by low yields in established synthetic routes. Here, we describe the optimization of the synthesis of 2-Se-uridine and 2-Se-thymidine derivatives by thermostable nucleoside phosphorylases in transglycosylation reactions using natural uridine or thymidine as sugar donors. Reactions were performed at 60 or 80 °C and at pH 9 under hypoxic conditions to improve the solubility and stability of the 2-Se-nucleobases in aqueous media. To optimize the conversion, the reaction equilibria in analytical transglycosylation reactions were studied. The equilibrium constants of phosphorolysis of the 2-Se-pyrimidines were between 5 and 10 and thus belong to the highest described so far. Thus, a ten-fold excess of sugar donor was needed to achieve 40-48% conversion to the target nucleoside. Scale-up of the optimized conditions provided four Se-containing nucleosides in 6-40% isolated yield which compares favorably to established chemical routes.<br>

The influence of pH in the tautomerism of 9,10-anthracenediols and 1,3-diketones

1986 ◽  
Vol 64 (1) ◽  
pp. 127-132
Author(s):  
John C. Anderson ◽  
A. Douglas Broadbent
Keyword(s):  
Total Concentration ◽  
Equilibrium Constants ◽  
Acid Base ◽  
Influence Of Ph

Equations have been derived to describe how the ratio of the total concentration of all keto forms to that of all enolic forms (K′) varies with changing pH, for a tautomeric system in which the enol and ketone are polyprotic acids. The influence of pH on the tautomerism of 2-amino-9,10-anthracenediol, 2,9,10-anthracenetriol, 2,4-pentanedione, and 1-(3-pyridyl)-1,3-butanedione was examined. The equilibrium constants for all the acid–base equilibria involved were calculated from the dependence of K′ on pH.

THERMAL ANALYSIS OF POLYANION METACHROMASY: EFFECT OF TEMPERATURE ON METACHROMATIC SOLUTIONS OF NUCLEIC ACIDS AND ACID MUCOPOLYSACCHARIDES

1969 ◽  
Vol 17 (10) ◽  
pp. 651-657 ◽  
Author(s):  
JOHN W. KELLY ◽  
LOUIS CHANG ◽  
FRED ROTHSTEIN
Keyword(s):  
Nucleic Acids ◽  
Toluidine Blue ◽  
Ribonucleic Acid ◽  
Equilibrium Constants ◽  
Linear Functions ◽  
Effect Of Temperature ◽  
A Value ◽  
Acid Mucopolysaccharides ◽  
Common Equation ◽  
Phosphate Groups

Spectra of toluidine blue with acid mucopolysaccharides and nucleic acids were recorded over the temperature range 10-70°C. Metachromatic ratios were inverse, linear functions of temperature. Intercepts and slopes of the thermal plots distinguished acid mucopolysaccharides from nucleic acids. Acid mucopolysaccharide reactions were thermally reversible. Nucleic acid reactions were not strictly reversible; such behavior was not attributable to thermal denaturation. An explanation for the unusual γ-peak of ribonucleic acid-toluidine blue metachromasy is offered in terms of terminal phosphate groups of ribonucleic acid. Solution data in which the polyanion-dye ratio was approximately 1, representing typical "metachromasy," were subjected to thermodynamic analysis. These data did not fit a common equation deriving equilibrium constants spectrophotometrically by variation of reactant concentrations. This failure supported the view of metachromasy as a phenomenon primarily involving dye-dye interaction. Another equation based only on temperature variation yielded a value of –4 kcal/mole for the chondroitin sulfate-toluidine blue complex, in good agreement with similar published values obtained both in solutions and stained materials.

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