Spectroscopic study of the competitive interaction between streptomycin and Evans blue to bovine serum albumin

The mechanism of the competitive interaction of streptomycin and Evans blue (EB) to bovine serum albumin (BSA) has been studied by using both fluorimetry and spectrophtometry. Effects of pH, streptomycin and concentration of EB on the competitive interaction of streptomycin and EB were examined. A static fluorescence quenching process was confirmed in the light of Stern–Volmer plot. The test result showed that there were strong and weak binding sites on BSA molecule and the binding constant of EB–BSA complex and the number of binding site n were obtained. These facts revealed that the competitive interaction was occurred between EB and streptomycin, which can possibly provide useful message in investigation of the interaction of antibiotic with BSA.

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► Streptomycin(SM) is a non-fluorescence drug molecule.
► Evans blue (EB) can quench the fluorescence of BSA.
► A static fluorescence quenching process was confirmed based of Stern–Volmer plot.
► We studied the competitive interaction of streptomycin (SM) and EB to BSA.
► SM displaced EB which bound to low affinity binding site on BSA from EB-BSA complex.