title: Investigation of the association behaviors between biliverdin and bovine serum albumin by fluorescence spectroscopy.
abstract: The interaction between biliverdin and bovine serum albumin (BSA) has been studied by steady fluorescence spectroscopy, synchronous fluorescence and resonance light scanning spectra. The binding of biliverdin to BSA quenches the tryptophan residue fluorescence and the results show that both static and dynamic quenching occur together with complex formation. The binding constant and binding sites of biliverdin to BSA at pH 7.1 are calculated to be 3.33x10(8)L/mol and 1.54, respectively, according to the double logarithm regression curve. In addition, the distance between the biliverdin and BSA is estimated to be 1.25nm using Föster's equation on the basis of the fluorescence energy transfer. Furthermore the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues has not obvious changes, which obeys the phase distribution model. Finally, the thermodynamic data show that biliverdin molecules enter the hydrophobic cavity of BSA via hydrophobic interaction.
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, PR China.
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Wei
authors.forename: Jian-Qing
authors.initials: JQ
authors.lastname: Li
authors.forename: Chuan
authors.initials: C
authors.lastname: Dong
authors.forename: Shao-Min
authors.initials: SM
authors.lastname: Shuang
authors.forename: Dian-Sheng
authors.initials: DS
authors.lastname: Liu
authors.forename: Carmen W
authors.initials: CW
authors.lastname: Huie