高等学校化学学报

高等学校化学学报 ›› 2001, Vol. 22 ›› Issue (1): 26.

• 研究论文 • 上一篇    下一篇

稀土离子与乳铁蛋白结合的光谱研究

朱兵1, 杜秀莲1, 李荣昌1, 王夔1, 金坚2, 王博诚2   

  1. 1. 北京大学药学院化学生物系, 北京 100083;
    2. 核医学国家重点实验室, 无锡 214063
  • 收稿日期:2000-04-07 出版日期:2001-01-24 发布日期:2001-01-24
  • 通讯作者: 王　夔(1928年出生),男,教授,博士生导师,中国科学院院士,从事生物无机及无机药物化学研究.
  • 基金资助:

    国家自然科学基金重大项目(批准号:29890280)资助

Spectroscopic Studies on the Binding of Lanthanides to the Apolactoferrin

ZHU Bing1, DU Xiu-Lian1, LI Rong-Chang1, WANG Kui1, JIN Jian2, WANG Bo-Cheng2   

  1. 1. Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China;
    2. National Key Laboratory of Nuclear Medicine, Wuxi 214063, China
  • Received:2000-04-07 Online:2001-01-24 Published:2001-01-24

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被引次数

82

摘要： 用紫外示差光谱、荧光光谱及圆二色谱等方法研究了Tb3+和Eu3+在pH7.4的条件下与乳铁蛋白及脱铁乳铁蛋白的结合作用.结果表明,Tb3+及Eu3+可特异性地结合在脱铁乳铁蛋白的两个Fe3+结合部位,但不能从已经结合铁的乳铁蛋白中把铁置换出来.测得Tb3+ 与这两个部位结合的条件平衡常数为lgK1=8.48±0.24和lgK2=6.72±0.18(25℃,0.10mol/L NaCl, 0.10mol/LHepes,pH=7.4). Tb3+在这两个位点结合时,蛋白质的构象发生变化.在 Tb3+ 与蛋白质的浓度比低时,构象趋于紧缩,色氨酸残基进入疏水的环境;当Tb3+结合得较多时,构象转而开放,色氨酸残基转向亲水性环境.但无论哪种情况,Tb3+与脱铁乳铁蛋白的结合都不影响蛋白的二级结构.

关键词: 乳铁蛋白, 脱铁乳铁蛋白, 稀土离子

Abstract: The binding of Tb 3+ and Eu 3+ to apolactoferrin has been studied on the basis of the changes in differential UV, fluorescence and CDspectra. It was found that Tb 3+ and Eu 3+ are able to bind to two ferric binding sites and the corresponding conditional equilibrium constants for the Tb 3+ binding were determined to be lg K1=8.48±0.24, lg K2=6.72±0.18(0.10 mol/L NaCl, 0.10 mol/L Hepes, pH7.4 and 25 ℃),but Tb 3+ can not displace the ferric ions from lactoferrin. By lower Tb 3+ /Lf ratio, the conformation became more compact with tryptophane residues exposed to more hydrophobic environment. When more Tb 3+ bound to Lf, the conformation changed in other direction. Anyhow, Tb 3+ binding did not affect the secondary structure.

Key words: Lactoferrin, Apolactoferrin, Lanthanide ions

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