Karale Ravikant R, Kamble Savita, Alwaleedy Suad, Kabara Komal B, Narwade Pallavi, Al-Hamdani Saeed Mohammed, Kumbharkhane Ashok C, Sarode Arvind V
School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded, Maharashtra, India.
Department of Physics, Taiz University, Taiz, Yemen.
J Biomol Struct Dyn. 2024 Dec 28:1-14. doi: 10.1080/07391102.2024.2445153.
The dielectric behavior of Asparagine (CHNO) in water over the frequency range of 10 MHz to 30 GHz in the temperature region of 278.15-303.15 K in a step of 5 K has been carried out using time domain reflectometry (TDR) at various concentrations of asparagine. The obtained dielectric spectra reveal two relaxation peaks. The low frequency relaxation is attributed to the interaction between solute-solute molecules, while the high frequency relaxation is due to the reorientation of solvent molecules. The various dielectric and thermodynamic parameters were calculated such as the dielectric constant (ε), relaxation time (τ), effective dipole moment (μ), Kirkwood correlation factor (g), hydration number or the number of solvent molecules effectively bounded to solute molecule (Z), effective volume of rotation (V), free energy of activation (ΔF), entropy of activation (ΔS) and enthalpy of activation (ΔH). The static dielectric constant (ε) shows increasing trend towards the higher concentration of asparagine, where as the high frequency dielectric constant (ε) decreases with the concentration of asparagine. The relaxation time of low frequency (τ) and high frequency (τ) processes increases towards higher concentration of solute molecule and also towards lower temperature. As the concentration of asparagine increases, the value of effective dipole moment (μ) decreases. With increasing amino acid concentrations hydration dynamics get affected and indicated by decreasing the hydration number (Z) but the hydration dynamics of aqueous asparagine was found least temperature dependent.
在278.15 - 303.15 K温度范围内，以5 K为步长，在10 MHz至30 GHz频率范围内，使用时域反射仪（TDR）对不同浓度天冬酰胺（CHNO）在水中的介电行为进行了研究。获得的介电谱显示出两个弛豫峰。低频弛豫归因于溶质 - 溶质分子之间的相互作用，而高频弛豫则是由于溶剂分子的重新取向。计算了各种介电和热力学参数，如介电常数（ε）、弛豫时间（τ）、有效偶极矩（μ）、柯克伍德相关因子（g）、水合数或有效结合到溶质分子上的溶剂分子数（Z）、有效旋转体积（V）、活化自由能（ΔF）、活化熵（ΔS）和活化焓（ΔH）。静态介电常数（ε）随着天冬酰胺浓度的增加呈上升趋势，而高频介电常数（ε）则随着天冬酰胺浓度的增加而降低。低频（τ）和高频（τ）过程的弛豫时间随着溶质分子浓度的增加以及温度的降低而增加。随着天冬酰胺浓度的增加，有效偶极矩（μ）的值降低。随着氨基酸浓度的增加，水合动力学受到影响，表现为水合数（Z）降低，但发现天冬酰胺水溶液的水合动力学对温度的依赖性最小。
