Abstract:

The interaction between zidovudine (ZDV) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy and ultraviolet-visible spectroscopy in aqueous solution (Tris-HCl buffer, pH 7.1). The effect of metal ions (Cu2+, Mg2+, Zn2+) on the interaction was also investigated. Results showed that the fluorescence intensity of BSA at 346 nm was quenched when zidovudine or metal ions were added. The quenching mechanism was a static quenching mechanism. A strong interaction exists between zidovudine and BSA. The thermodynamic parameters △H and △S were -10.2 kJ·mol-1 and 77.5 J·mol-1·K-1 at 298 K, respectively, indicating that electro-static forces played a major role. The binding constant, the number of binding site and the binding distance were 6.92×105 L·mol-1, 1.18, and 2.28 nm at 298 K, respectively. The binding constant and the number of binding sites decreased with the increase in temperature. The metal ions, Cu2+, Mg2+ and Zn2+, all decreased the binding constant and increased the binding distance for binding between ZDV and BSA.

Key words: Bovine serumalbumin, Zidovudine, Metal ion, Fluorescence quenching