Study Of The Interaction Between Serum Albumin And Analogs Of Biphenyldicarboxylate By Spectrofluorimetry

In recent years, the studies of biological macromolecules has been become an interesting topic for many researchers such as biology, chemistry and clinical medical workers and so on. Especially the investigating of the binding mechanism between drug molecules and proteins, it not only helps us to understand the pharmacology and the effects of drugs, but also can provide valuable theory basis for design and development new medicines.This work was designed to study the interaction between serum albumin and Biphenyldicarboxylate (DDB) or analogs of DDB by fluorescence spectroscopy in combination with UV absorption spectrum under physiological conditions for the first time. Results showed that both DDB and analogs had a strong ability to quench the intrinsic fluorescence of serum albumin through a static quenching procedure. The binding constants (K) were calculated according to the relevant fluorescence datas. The thermodynamic parameters (△H,△S and△G) showed that hydrophobic force played a major role in the binding interaction between serum albumin and DDB or analogs. According to Foster’s non-radiative energy transfer theory, the extent of overlap of the emission spectrum of serum albumin with the absorption spectrum of DDB and analogs were evaluated, the values of r for proteins-drug were all less than7nm, which indicated that the fluorescence quenching between serum albumin and DDB or analogs were also a non-radiative transfer process. Synchronous fluorescence spectra and fluorescence contour plots of serum albumin were investigated in the presence of DDB or analogs, which suggested that the binding of DDB (or analogs) to serum albumin can induce conformational changes in the proteins. The comparison between DDB and analogs were made, and results showed that the interaction between DDB or analogs with albumin were differences, it may caused by that they had different functional groups. Through the studies on the activity relationship between DDB and analogs, change specific groups of DDB, thereby can synthetize higher biological activity compounds.