Abstract:The interaction between the polyoxometalate K10C4H4FN2O2Sm(PW11O39)2·12.5H2O (FSPW) and Bovine Serum Albumin (BSA) was investigated by using fluorescence and UV/vis. The experimental results show that the regular fluorescence quenching of BSA is caused by the compound FSPW. According to the UV-visible absorption spectra, the fluorescence quenching of BSA is caused by the formation of FSPW-BSA complex, and it is a static quenching. The ?驻G of the process of interaction between the compound FSPW and BSA is less than zero, which indicates that this process is a spontaneous process. The ?驻H and ?驻S are both less than zero, which shows that the binding process of FSPW and BSA is an exothermic molecular interaction, in which the hydrogen bond and van der Waals' force play the major role. The results of synchronous fluorescence spectroscopy show that FSPW is strongly bound with BSA by inserting into the hydrophobic cavity of the protein, and the binding process causes the change of protein conformation. The binding site is close to the tryptophan residue.