羟基类氨基酸与醇在水溶液中的异系焓相互作用

目的 为揭示蛋白质的稳定机制、蛋白质变性的原因、蛋白质工程设计和生物大分子与小分子间的相互作用提供溶液热力学依据。方法 利用2277热活性检测仪的流动测量系统测定了298．15K时L-丝氨酸、L-苏氨酸分别与不同醇在水溶液中的混合过程焓变以及各自的稀释焓，依据McMillan-Mayer理论关联得到异系焓相互作用系数。结果 获得了大量的混合焓和稀释焓数据，利用异系焓相互作用系数讨论了羟基类氨基酶与醇的作用机制。提出用疏水基团与亲水基团的数目比值(n疏水／n亲女)来预测hxy的差别，发展了基团贡献法(SWAG)。结论 hxy为正值，羟基类氨基酸与醇相互作用过程中吸热效应为主，疏水效应占主导地位，表明在蛋白质由一级结构形成疏水内核折叠成二级结构的过程中羟基类氨基酸仍表现出一定的疏水性。

Heterotactic enthalpic interaction between hydroxyl amino acidand alcohol in aqueous solutions at 298.15K

Objective: To obtain the information about solute solvation and solute interactions in aqueous media, and a better understanding of their role played in the conformational stability and unfolding behavior of proteins. Methods: The mixing of heterotactic enthalpies and dilution of aqueous alcohol solutions and aqueous hydroxyl amino acid solutions (L-serine, L-threonine) were determined at 298.15K by 2277 Thermal Activity Monitor of flow microcalorimetric system. The data were analyzed according to the McMillon-Mayer theory to obtain the enthalpic interaction coefficients. Results: The action mechanism of different amino acids and alcohol molecules was discussed. The difference of hxy was pointed out and SWAG by the ratio of hydrophobic group and hydrophilic group was improved upon. Conclusion: The values of h xy is positive, the hydrophobicity acts dominantly. Hydroxyl amino acid will give hydrophoby in folding behavior of the proteins.