物理化学学报 >> 2000, Vol. 16 >> Issue (04): 351-355.doi: 10.3866/PKU.WHXB20000411

研究论文 上一篇    下一篇

胶束溶液中某些氨基酸和二肽的解离常数

张向东, 刘岩, 孙锦玉, 刘祁涛   

  1. 辽宁大学化学科学与工程学院,沈阳 110036
  • 收稿日期:1999-09-20 修回日期:1999-12-10 发布日期:2000-04-15
  • 通讯作者: 张向东

Effect of SDS Micelle on the Protonation Constants on some Aminoacids and Dipeptide

Zhang Xiang-Dong, Liu Yan, Sun Jin-Yu, Liu Qi-Tao   

  1. Chemical Science and Engineering College,Liaoning University,Shenyang 110036
  • Received:1999-09-20 Revised:1999-12-10 Published:2000-04-15
  • Contact: Zhang Xiang-Dong

摘要:

用pH电位法测定了在SDS(十二烷基磺酸钠)胶束溶液中甘氨酰丙氨酸和六种氨基酸(甘氨酸、丙氨酸、缬氨酸、亮氨酸、异亮氨酸、苯丙氨酸)的两级酸解离常数 pKa1 和 pKa2,发现与水溶液相比, pKa 值均显著增加 ,即SDS胶束形成强烈抑制质子解离. 结合1HNMR测定结果 ,讨论了pKa1和 pKa2 随SDS浓度的变化规律以及与各配体自身结构的关系.

关键词: 解离常数, SDS胶束, 氨基酸, 二肽

Abstract:

The protonation constants of six aminoacids (glycine, analine, valine, leucine, isoleucine, and phenylalanine)and alycylalanine in SDS micelle solution have been determined by potentiometric pH titration technique at 25.0+0.1℃and at 0.10 mol•dm-3 ionic strength(NaNO3). It is found that all of the protonation constants in SDS solution increase remarkably as compare with these in aqueous solution. This means that SDS micelle depresses strongly the dissociation of proton .The reasons leading to the results and the rule of change of the protonation constants pKa1 and pKa2 with the concentration of SDS and the structure of these aminoacids and dipeptide are discussed by the pH titration data and 1H NMR research results.

Key words: Protonation constant, SDS Micelle, Aminoacid, Dipeptide