Interaction of Indigo Disulfonate and Bovine Serum Albumin

The interaction between indigo disulfonate (IDGS) and bovine serum albumin (BSA) in Tris-HCl buffer medium of pH 7.0 was studied by fluorophotometry and absorptiophotometry.The interaction distance (r) between molecules of IDGS and tryptophan radical of BSA,the energy transfer efficiency (Ea) and the critical energy distance (R0) were calculated according to the Frster′s theory,and the values found were 3.63 nm,0.44 and 2.44 nm respectively.It was shown that the mechanism of the interaction is a static and dynamic process involving energy transfering.