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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.


Intramolecular H-bond of serine.
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fig13: Intramolecular H-bond of serine.

Mentions: Serine is α-amino acid containing three functional groups (–OH, –NH2, and COOH), but only two protonation equilibria are determined corresponding to the protonation of amino and carboxylate groups, respectively. This can be attributed to the fact that, as the relative pH in most experiments did not extend to pH > 12, the protonation constant for the aliphatic OH group in serine could not be measured. Also, a qualitative explanation could be based on the formation of an intramolecular hydrogen bond as depicted in Figure 13. Assume that the proton on this –OH group is more difficult to remove in the amino acid form.


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)

Intramolecular H-bond of serine.
© Copyright Policy
Related In: Results  -  Collection

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

fig13: Intramolecular H-bond of serine.
Mentions: Serine is α-amino acid containing three functional groups (–OH, –NH2, and COOH), but only two protonation equilibria are determined corresponding to the protonation of amino and carboxylate groups, respectively. This can be attributed to the fact that, as the relative pH in most experiments did not extend to pH > 12, the protonation constant for the aliphatic OH group in serine could not be measured. Also, a qualitative explanation could be based on the formation of an intramolecular hydrogen bond as depicted in Figure 13. Assume that the proton on this –OH group is more difficult to remove in the amino acid form.

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.