[Study on the interaction between brucine and bovine serum albumin]

The interaction between brucine and bovine serum albumin (BSA) was investigated using fluorescence spectroscopy (FS) and ultraviolet spectroscopy (UV). The experimental results showed that the brucine quenches the inner fluorescence by forming a brucine-BSA complex. It was found that both static quenching and non-radiation energy transfer were the main reasons for the fluorescence quenching. The apparent binding constants (K(A)) between brucine and BSA were 6. 3 x 10(3) (27 degrees C) and 7.7 x 10(3) (37 degrees C), and the binding sites (n) were 0.94 (27 degrees C) and 0.97 (37 degrees C). According to the Förster theory of non-radiation energy transfer, the binding distances (r) were also obtained. The process of binding was a spontaneous molecular interaction in which entropy increased and Gibbs free energy decreased, indicating that the interaction between brucine and BSA was driven mainly by hydrophobic force.