The irreversible electrochemical behavior of bis-benzimidazole derivative (BBID) and the interaction of BBID with DNA were studied by cyclic voltammetry, differential pulse voltammetry, chronocoulometry, bulk electrolysis and scan electrochemical microscope technique. An electrochemical equation suitable for studying the interaction of irreversible redox molecule with DNA was obtained. The equation can be used to detect the binding constant (K) and binding site size (s) of BBID on DNA easily and rapidly. The experiments have proved that the main interactions between BBID and the natural fish sperm DNA were sequence mediated and structure mediated. BBID bound tightly to minor groove of the DNA which covered four base pairs.

Key words: ELECTROCHEMICAL METHOD, DIBENZO COMPOUNDS, BENZIMIDAZOLE P, DEOXYRIBONUCLEIC ACID, INTERACTIONS, ELECTROCHEMICAL REACTION