[DL-α-丙氨酸及脂肪族系列二肽在KCl水溶液中的溶解焓]

[Dissolution enthalpies of DL-alpha-alanine and dipeptides of aliphatic series in aqueous solutions of KCl].

作者信息

Mezhevoĭ I N, Badelin V G

出版信息

Biofizika. 2009 Nov-Dec;54(6):984-7.

PMID:20067174

Abstract

The integrated enthalpies of dissolution DeltasolH(m) of DL-alpha-alanine, DL-alpha-alanyl-glycine, DL-alpha-alanyl-beta-alanine, DL-alpha-alanyl-DL-alpha-alanine and L-alpha-alanyl-L-alpha-alanine in mixtures of water with KCl have been measured at concentrations of electrolyte up to 4 mole/kg (T=298.15 K). On the basis of the data obtained, the standard enthalpies of dissolution (DeltasolH(0)) and transfer (DeltatrH(0)) of the amino acids and dipeptides from water to aqueous solutions with KCl were determined. It was found that the dependences DeltatrH(0) = f(X2) for all systems have extreme character, which indicates different mode of interactions between the components of the solution in different ranges of electrolyte concentration. Within the framework of the formalism of the McMillan-Mayers theory, the enthalpic pair coefficients of interaction of hxy biomolecules with KCl estimated. The coefficients are discussed in terms of the integral enthalpic effects of interactions between the components in aqueous solutions and the structural features of solutes.

摘要

已在高达4摩尔/千克的电解质浓度下（T = 298.15 K）测量了DL-α-丙氨酸、DL-α-丙氨酰甘氨酸、DL-α-丙氨酰-β-丙氨酸、DL-α-丙氨酰-DL-α-丙氨酸和L-α-丙氨酰-L-α-丙氨酸在水与KCl混合物中的溶解积分焓DeltasolH(m)。根据所得数据，确定了氨基酸和二肽从水到含KCl水溶液的标准溶解焓（DeltasolH(0)）和转移焓（DeltatrH(0)）。发现所有体系的DeltatrH(0) = f(X2)依赖关系具有极值特征，这表明在不同电解质浓度范围内溶液各组分之间的相互作用方式不同。在麦克米兰 - 迈尔斯理论形式体系的框架内，估算了hxy生物分子与KCl相互作用的焓对系数。根据水溶液中各组分相互作用的积分焓效应和溶质的结构特征对这些系数进行了讨论。