物理化学学报 >> 2006, Vol. 22 >> Issue (08): 1034-1039.doi: 10.3866/PKU.WHXB20060825

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脂肪族α-氨基酸疏水自缔合作用的流动微量热法研究

胡新根;于丽;林瑞森;方盈盈;李文兵   

  1. 温州大学化学与材料科学学院;山东大学胶体与界面化学教育部重点实验室, 济南 250100;浙江大学化学系, 杭州 310027
  • 收稿日期:2006-02-21 修回日期:2006-05-08 发布日期:2006-08-04
  • 通讯作者: 胡新根 E-mail:hxgwzu@126.com

Study on Hydrophobic Self-association of Aliphatic α-amino Acids by Flow Microcalorimetry

HU Xin-Gen;YU Li;LIN Rui-Sen;FANG Ying-Ying;LI Wen-Bing   

  1. School of Chemistry and Materials Science, Wenzhou University Zhejiang Wenzhou 325027, P. R. China;Key Laboratory for Colloid and Interface Chemistry of State Education Ministry, Shandong University, Jinan 250100, P. R. China;Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China；
  • Received:2006-02-21 Revised:2006-05-08 Published:2006-08-04
  • Contact: HU Xin-Gen E-mail:hxgwzu@126.com

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摘要： 建立了水溶液中脂肪族α- 氨基酸疏水自缔合相互作用的化学模型, 根据模型方程对由精密流动微量热法测得的α- 氨基酸水溶液的稀释焓数据进行回归分析, 得到等步自缔合作用的平衡常数(K)、焓变(ΔHm)和熵变(ΔSm)等热力学参数, 发现焓、熵之间存在很好的补偿关系. 同时计算了溶液中水的偏摩尔过量熵(SE1), 并根据脂肪族α- 氨基酸的水化模型对结果进行了讨论. 建立的化学模型参数能在一定程度上解释McMillan- Mayer模型中的同系焓作用系数的物理意义.

关键词: α-氨基酸, 疏水自缔合, 化学模型, 稀释焓, 流动微量热

Abstract: A chemical interaction model has been established for the hydrophobic self- association of aliphatic α- amino acids in aqueous solutions. In order to obtain the parameters of the model equation, dilution enthalpies of 5 aliphatic α- amino acids aqueous solutions have been measured at 298.15 K by flow microcalorimetry. The equilibrium constants (K), enthalpy change (ΔHm) and entropy change (ΔSm) have been determined for the equal- step association. It was found that between enthalpy and entropy exists a good compensation relationship. In addition, partial molar excess entropies of water in solutions (SE1) were calculated, and were discussed according to the hydration model for aliphatic α- amino acids. Noteworthily, the parameters in the model equation can be used to explain the homogeneous enthalpic interaction coefficients in McMillan- Mayer model to some extent.

Key words: α-amino acids, Hydrophobic self-association, Chemical model, Dilution enthalpy, Flow microcalorimetry