Study of the Solubility and Transfer Thermodynamics of d,l-Phenylalanine in Aqueous Sodium Chloride and d,l-Serine in Aqueous Sodium Nitrate Solutions

Electrolytic Effect on the Solubility and Solvation Thermodynamics of l-Serine and l-Isoleucine in Aqueous Media

“…The different trend in solubility in aqueous electrolytic solutions having different cations and anions might be due to size-dependent dispersion and hydrogen bonding interactions with amino acid molecules. In the present study, it is important to note that the sizes of NaNO 3 (0.628 nm) , and the amino acid l -serine (0.593 nm) are very much similar. This induces stronger hydrogen bonding and size-dependent dispersion interactions.…”

“…That is why the hydrated Na + is more stable than K + in the first hydration zone. 18 In the case of L-isoleucine, the change of the TΔS t, ch 0 (i) value shows a similar trend like in L-serine but shows a lower positive value. In this case, the positive trend of TΔS t, ch 0 (i) is more in NaNO 3 solution than that in KNO 3 solution.…”

“… a Diameters of NaNO 3 and KNO 3 are 0.628 and 0.700 nm, , respectively. Dipole moments of NaNO 3 and KNO 3 are 15.07 and 16.8D, respectively. , …”

“…The cation Na + has relatively smaller size and higher cationic charge density than the larger K + . That is why the hydrated Na + is more stable than K + in the first hydration zone …”

“…Amino acids have been important not only in the biological ground but also in various fields of industry like chemical, food, pharmaceutical, foundation, and eco-friendly plastics for a long time. − Information about the solubility of protein building units, that is, amino acids in various cosolvent mixtures in the presence and absence of electrolytes, is noteworthy for researchers in the pharmaceutical field as this is involved in drug purification, preformulation analysis, and design of pharmaceutical dosage. , Different thermodynamic parameters like free energy are related to the solubilities of these molecules. Temperature plays a crucial role in characterizing the interaction between ions and small molecules with biomolecules in the experimental solution. − A lot of studies on amino acids have established that their solubilities and solvation thermodynamics determine their biochemical role in animal metabolism. − In many cases, it has been seen that thermodynamic parameters were very much helpful in characterizing the conformational changes of biomacromolecules such as proteins. , With the addition of electrolytes in the solution of these molecules, the chemical reactivity and zwitterionic characters have been seen to direct other biophysical roles such as protein folding and unfolding. − Otherwise, amino acids are usually used as model compounds for more complex molecules like proteins. However, a more attentive study of the electrolytic effect on amino acid solution is still enviable to expose the molecular type of interaction between electrolyte ions and protein functional groups. , That is why in this study, we started a project regarding the solubility and solvation thermodynamics of some amino acids in aqueous electrolyte solutions.…”