Determination of the pKa value of the hydroxyl group in the alpha-hydroxycarboxylates citrate, malate and lactate by 13C NMR: implications for metal coordination in biological systems. Bio- metals 22, 771-778.Silva, A. M. N., Kong, X. L., and Hider, R. C. (2009) Determination of ...
(pH < 2), the two amines are protonated and the four phenols are in theirhydroxylform, thus ristocetin bears two positive charges. As the pH increases, the phenolic groups start to ionize with negative charges. At neutral pH (pH = 7.0) which is also the pKa of one phenolic group, ...
Regulation of protein phosphorylation is mainly con- trolled by various kinases, a class of enzymes that catalyze the transfer of the phosphoryl group from adenosine triphosphate (ATP) to the hydroxyl group of proteins. Among over 500 known kinases2, protein kinase A (PKA) is one of the most...
In carboxylic acids, the carbon atom is bonded to the oxygen atom by a double bond and a hydroxyl group by a single bond. Proteins consist of amino...Become a member and unlock all Study Answers Start today. Try it now Create an account Ask a question Our exp...
3A). The hydroxyl group of the Thr-73 side chain participates in a helix-capping interaction with the main-chain amide group of Glu-76 at the N terminus of helix αB in the “N” SH2 domain. Similarly, the hydroxyl group of the Ser-189 side chain forms a helix cap with the main-...
were also restored on supplementation with quercetin37. Being lipophilic due to multiple methylation of hydroxyl groups, quercetin may penetrate into the brain and modulate pharmacological functions38. The protective changes of quercetin were attributed to its antioxidant potential and capability to preserve...
However, the introduction of a hydroxyl group at the 4-position or at the 2′-position of the aromatic ring of hydroxybenzophenones would decrease greatly their p K a1 values. Thus the presence of this type of hydrogen bonding also plays an important role in the acid dissociation of these ...
and its Nϵ2 atom is solvent inaccessible and accepts a hydrogen bond from the hydroxyl group of Thr 168, both protonation and phosphorylation of His 189 must be accompanied by a change in the side-chain conformation of His 189, specifically from a X2 angle in the g+ conformer in the ...
The parameters tested for their ability to represent the variations observed in the experimental pKa(s) are atomic and molecular properties including Mulliken charge on the oxygen atom of the hydroxyl group, the LUMO and HOMO energies, the LUMO-HOMO energy gap 螖 and the dipole moment . The ...
Studies the catalysis of glutathione S-transferase A1-1 product release by the anomalous pK[sub a] of the hydroxyl group Tyr-9. Site directed mutagenesis and protein expression and purification; Equilibrium binding affinity; Kinetics of ligand binding and dissociation.Ibarra...