Acta Chimica Sinica ›› 2005, Vol. 63 ›› Issue (18): 1727-1732. Previous Articles     Next Articles

Original Articles



  1. (1长江大学化学与环境工程学院 荆州 434020)
    (2武汉大学化学与分子科学学院 武汉 430072)
  • 投稿日期:2004-12-27 修回日期:2005-05-20 发布日期:2010-12-10
  • 通讯作者: 颜承农

Fluorescence Spectra of the Binding Reaction between Paraquat and Bovine Serum Albumin

YAN Cheng-Nong*,1, ZHANG Hua-Xin1, LIU Yi2, MEI Ping1, LI Ke-Hua1, TONG Jin-Qiang1   

  1. (1 College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020)
    (2 College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072)
  • Received:2004-12-27 Revised:2005-05-20 Published:2010-12-10
  • Contact: YAN Cheng-Nong

Under the imitated physiological condition of animal body, the binding of paraquat to bovine serum albumin (BSA) was studied by fluorescence spectrum and ultra-violet spectrum. It was shown that this compound has a quite strong ability to quench the fluorescence launching from BSA. After analyzing the fluorescence quenching data according to Stern-Volmer equation and Lineweaver-Burk double-reciprocal equation, we found that BSA had reacted with paraquat and formed a certain new compound. The quenching belonged to static fluorescence quenching, with non-radiation energy transfer happening within single molecule. The binding locality was an area 2.07 nm away from tryptophan residue-212 in BSA based on F?rster’s non-radiation energy transfer mechanism. According to Lineweaver-Burk equation, KLB (297 K: 2.035×104 L•mol-1; 304 K: 3.256×104 L•mo-1; 311 K: 2.889×104 L•mol-1), the forming constants of the compound at different temperatures and the thermodynamic parameters (⊿HØ=18.50 kJ•mol-1; ⊿SØ=144.7 J•K-1/145.2 J•K-1/141.0 J•K-1; ⊿GØ=-24.50 kJ•mol-1/-25.66 kJ•mol-1/-25.36 kJ•mol-1) at correspondence temperatures were obtained. The latter shows that binding power between them is mainly the hydrophobic interaction. The effect of paraquat on the conformation of BSA was analyzed by three-dimensional fluorescence spectra, contour spectra and synchronous spectra, and some useful information was offered for preventing animals from infecting paraquat and curing those who had caught it.

Key words: paraquat, bovine serum albumin, binding reaction, thermodynamic parameter, absorption spectra, three-dimensional fluorescence spectra