物理化学学报 >> 1996, Vol. 12 >> Issue (09): 804-808.doi: 10.3866/PKU.WHXB19960906

研究论文 上一篇    下一篇

三吡啶胺Zn(II)配合物作为碳酸酐酶模拟物的研究

寇福平,林华宽,朱守荣,陈荣悌   

  1. 南开大学化学系,天津 300071
  • 收稿日期:1996-03-19 修回日期:1996-05-20 发布日期:1996-09-15
  • 通讯作者: 林华宽

A Zinc(II) Complex of Tripyridylamine(TPA) as a Model for Carbonic Anhydrase

Kou Fu-Ping,Lin Hua-Kuan,Zhu Shou-Rong,Chen Rong-Ti   

  1. Department of Nankai University,Tianjin 300071
  • Received:1996-03-19 Revised:1996-05-20 Published:1996-09-15
  • Contact: Lin Hua-Kuan

摘要:

利用pH电位滴定法,在25±0.1℃,I=0.1mol•dm-3KNO3条件下,测定了三吡啶胺(TPA)的质子化常数和三吡啶胺Zn(II)配合物中配位水的解离常数.结果表明,该配合物中与Zn(II)配位的H2O分子的电离常数显著下降,测得pKa为7.8.在25±0.1℃,I=0.1mol•dm-3NaClO4条件下,pH=6~9(三羟甲基氨基甲烷缓冲溶液,20mmol•dm-3)范围内,用紫外-可见分光光度法考察了该配合物催化对硝基苯酚乙酸酯(NA)水解的动力学行为,得到了配合物催化酯水解的二级反应速率常数kNP,其最大值为3.32×10-2(mol•dm-3)-1•s-1热力学、动力学的研究结果均说明,三吡啶胺Zn(II)配合物中与Zn(II)配位的OH-是较好的亲核试剂,该配合物是一个较好的碳酸酐水解酶的模拟物.

关键词: 碳酸酐水解酶, 模拟物, 亲核试剂, 速率常数

Abstract:

The protonation constant of TPA and, in its 1:2 (Zn(II):L) complex, the deprotonation constant of H2O coordinated to Zn(II) have been determined by pH titration at 25±0.1℃, I=0.1 mol•dm-3 KNO3. They are 4.29 and 7.8, respectively. It is worthy to be noted that the H2O bound to Zn(II) could deprotonate easily near physiology pH. A kinetic study of 4-nitrophenyl acetate(NA) hydrolysis by Zn(II)(TPA)2•H2O complex in 10%(v/v) CH3CN at 25±0.1℃, I=0.1 mol•dm-3 NaClO4, and pH range 6~9(20mmol•dm-3 Tris buffer),has been carried out. The maximum value of second-order rate constant k((mol•dm-3)-1•s-1) obtained is 3.32×10-2. Thus, Our present model study shows that, like the Zn(II)-enzymes, the Zn(II)-bound OH- in complex can act as a good nucleophile agent to the carbonyl carbons, the Zn(II) complex of TPA is a good model for carbonic anhydrase.

Key words: Carbonic anhydrase, Model, Nucleophile agent, Rate constant