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Protonation equilibria of biologically active ligands in mixed aqueous organic solvents.

El-Sherif AA, Shoukry MM, Abd Elkarim AT, Barakat MH - Bioinorg Chem Appl (2014)

Bottom Line: The review is mainly concerned with the protonation equilibria of biologically active ligands like amino acids, peptides, DNA constituents, and amino acid esters in nonaqueous media.Equilibrium concentrations of proton-ligand formation as a function of pH were investigated.Also, thermodynamics associated with protonation equilibria were also discussed.

View Article: PubMed Central - PubMed

Affiliation: Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt ; Department of Chemistry, Faculty of Arts and Science, Northern Border University, Rafha, Saudi Arabia.

ABSTRACT
The review is mainly concerned with the protonation equilibria of biologically active ligands like amino acids, peptides, DNA constituents, and amino acid esters in nonaqueous media. Equilibrium concentrations of proton-ligand formation as a function of pH were investigated. Also, thermodynamics associated with protonation equilibria were also discussed.

No MeSH data available.


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Mentions: (3) Protonation Equilibria of L-Lysine and Histidine in Mixed Water-Ethanol Medium (Figure 3). L-lysine contains –NH2 group in the side chain. Due to the fact that this amino group is far from the carboxyl groups, resulting in a lesser degree of inductive effect, it can be said that log⁡10⁡K1 is related to the protonation of this amino group. The second and third protonation equilibria belong to the α-amino and carboxyl groups, respectively. For L-histidine, the log⁡10⁡K1 and log⁡10⁡K2 values are related to the protonation of –NH2 and the nitrogen in imidazole groups, respectively. The third constant (log⁡10⁡K3) belongs to the protonation of the carboxylate group.


Protonation equilibria of biologically active ligands in mixed aqueous organic solvents.

El-Sherif AA, Shoukry MM, Abd Elkarim AT, Barakat MH - Bioinorg Chem Appl (2014)

© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150405&req=5

Mentions: (3) Protonation Equilibria of L-Lysine and Histidine in Mixed Water-Ethanol Medium (Figure 3). L-lysine contains –NH2 group in the side chain. Due to the fact that this amino group is far from the carboxyl groups, resulting in a lesser degree of inductive effect, it can be said that log⁡10⁡K1 is related to the protonation of this amino group. The second and third protonation equilibria belong to the α-amino and carboxyl groups, respectively. For L-histidine, the log⁡10⁡K1 and log⁡10⁡K2 values are related to the protonation of –NH2 and the nitrogen in imidazole groups, respectively. The third constant (log⁡10⁡K3) belongs to the protonation of the carboxylate group.

Bottom Line: The review is mainly concerned with the protonation equilibria of biologically active ligands like amino acids, peptides, DNA constituents, and amino acid esters in nonaqueous media.Equilibrium concentrations of proton-ligand formation as a function of pH were investigated.Also, thermodynamics associated with protonation equilibria were also discussed.

View Article: PubMed Central - PubMed

Affiliation: Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt ; Department of Chemistry, Faculty of Arts and Science, Northern Border University, Rafha, Saudi Arabia.

ABSTRACT
The review is mainly concerned with the protonation equilibria of biologically active ligands like amino acids, peptides, DNA constituents, and amino acid esters in nonaqueous media. Equilibrium concentrations of proton-ligand formation as a function of pH were investigated. Also, thermodynamics associated with protonation equilibria were also discussed.

No MeSH data available.