The interaction between desferrioxamine and hemin: a potential toxicological implication.

Our previous research demonstrated that iron chelating agent desferrioxamine (DFO) could promote iron donor hemin-induced protein oxidation due to the combination of DFO and hemin, but the binding constant and thermodynamic parameters of DFO-hemin interaction have not been examined before. In this study, affinity capillary electrophoresis (ACE) was applied to investigate the interaction between DFO and hemin for the first time. The binding constants of DFO-hemin were calculated to be 10(4)-10(5)M(-1) at various temperatures. The negative value of various thermodynamic parameters (ΔG, ΔS, and ΔH) suggested that the binding was spontaneous and the interaction was exothermic and entropically driven. In addition, the high binding affinity between DFO with hemin seemed to be the key factor on promoting hemin- catalyzed formation of cytotoxic radicals, such as superoxide (O(2)(-)), which was related to the potential toxicity of this drug in clinical use.