Spectroscopic Studies on the Interaction of Efonidipine with Bovine Serum Albumin

The binding of efonidipine to bovine serum albumin (BSA) was investigated by fluorescence spectroscopy and circular dichroism (CD) technique. The quenching mechanism of fluorescence BSA by efonidipine showed that efonidipine quenched the fluorescence of tryptophan residue mainly through the collision mode. The thermodynamic parameters DeltaH0 and DeltaS0 were calculated to be 75.95 kJldrmo^-1 and 342.32 kJldrmol^-1, respectively, indicating that the hydrophobic force played a major role. The results of CD spectrum and synchronous fluorescence spectrum showed that the binding of efonidipine to BSA leads to conformational change of BSA. Binding studies in the presence of ANS indicated that efonidipine competed with ANS for hydrophobic sites on BSA. The effects of metal ion on the binding constant of efonidipine-BSA complex were also investigated.