Epirubicin is used to treat the fast multiplication cancer. The interaction of Epirubicin-Fe^2＋ system with calf thymus DNA has been investigated using UV spectra, fluorescent spectra, CD, viscosity and cyclic voltammetry etc. The results show that Epirubicin can form constant system with Fe^2＋ in pH＝7.4 solution. Hypochromism was observed in the UV spectra of the system in the presence of the DNA. The Scatchard plots showed competitive inhibition aganist EB binding to DNA. The relative viscosity and thermal deformation temperature of DNA increased with addition of the Epirubicin-Fe^2＋ system. The fluorescence polarization of the DNA-EB system increased with addition of the Epirubicin-Fe^2＋ system. Determination of cyclic voltammetry showed that the DNA made the Epirubicin-Fe^2＋ formal potential positively shift. The energy of base pair has been weakened with addition of the Epirubicin-Fe^2＋ system. So it can be concluded that the binding mode of the Epirubicin-Fe^2＋ system with CT DNA belongs to intercalation action. This work may be usefully applied to elucidating the mechanisms of natural nucleases and drug design.

Key words: Epirubicin-Fe^2＋ system, calf thymus DNA, Scatchard plot