[Investigation of interaction between catechin and bovine serum albumin by spectroscopic methods].
In the present work, the interaction of catechin with bovine serum albumin (BSA) under physiological condition was studied by fluorescence quenching spectra in combination with Fourier transform infrared (FTIR) spectroscopy. The binding constants, the drug-binding mode, the binding site between catechin and BSA in aqueous solution at pH 7.40, and the effect of common ions were studied. The results show that catechin has the ability to quench the intrinsic fluorescence of BSA because of a complex formed, and the quenching mechanism is static quenching. The binding constants K under 296, 303 and 310 K were 2.368, 2.249 and 2.152 x 10(6) L x mol(-1) respectively. The thermodynamic parameters showed that the interaction between catechin and BSA was driven mainly by hydrophobic force and electrostatic interaction. The displacement experiment shows that catechin can bind to the site I of BSA. The distance between the 214 tryptophan residues in BSA and catechin was estimated to be 1.46 nm using Foster's equation on the basis of fluorescence energy transfer. According to FTIR, the secondary structure of BSA changed when catechin was added.
Zhang
Hai-Rong
HR
Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Education, Guangxi Normal University, Guilin 541004, China. zhanghairong1023@sohu.com
Bian
He-Dong
HD
Pan
Ying-Ming
YM
Tian
Jian-Niao
JN
Yu
Qing
Q
Liang
Hong
H
Chen
Zhen-Feng
ZF
D002392:Catechin / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D014364:Tryptophan / Q000737:chemistry
D012710:Serum Albumin, Bovine; D014364:Tryptophan; D002392:Catechin