title: Comparative study of the interactions between ovalbumin and three alkaloids by spectrofluorimetry.
abstract: The interaction between ovalbumin (OVA) and three purine alkaloids (caffeine, theophylline and diprophylline) was investigated by the aid of intrinsic and synchronous fluorescence, ultraviolet-vis absorbance, resonance light-scattering spectra and three-dimensional fluorescence spectra techniques. Results showed that the formation of complexes gave rise to the fluorescence quenching of OVA by caffeine, theophylline, and diprophylline. Static quenching was confirmed to results in the fluorescence quenching. The binding site number n, apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures. The binding process was spontaneous molecular interaction procedures in which both enthalpy and Gibbs free energy decreased. Van der Waals forces and hydrogen bond played a major role in stabilizing the complex. The comparison between caffeine, theophylline, and diprophylline was made, and thermodynamic results showed that diprophylline was the strongest quencher and bound to OVA with the highest affinity among three compounds. The influence of molecular structure on the binding aspects was reported.
authors.affiliation: The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
authors.forename: Rui-Qiang
authors.initials: RQ
authors.lastname: Wang
authors.forename: Yu-Jing
authors.initials: YJ
authors.lastname: Yin
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Juan-Juan
authors.initials: JJ
authors.lastname: Pu
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Huan-Jing
authors.initials: HJ
authors.lastname: Dou
authors.forename: Chuan-Jun
authors.initials: CJ
authors.lastname: Song
authors.forename: Rui-Yong
authors.initials: RY
authors.lastname: Wang
mesh_terms: D001665:Binding Sites; D002110:Caffeine / Q000737:chemistry*; D004400:Dyphylline / Q000737:chemistry*; D005453:Fluorescence; D006860:Hydrogen Bonding; D015394:Molecular Structure; D010047:Ovalbumin / Q000737:chemistry*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013806:Theophylline / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D004400:Dyphylline; D002110:Caffeine; D010047:Ovalbumin; D013806:Theophylline