The interaction between [Cu(phen) (H-20) (L-Met)] ~+ (phen = 1, 10- phenanthroline and L-Met = L-methionine) and calf thymus DNA in phosphate buffer (pH = 6.86) has been investigated by electrochemical techniques ( cyclic voltammetry, differential pulse voltammetry, ac impedance and its data fitting), viscosity measurements, electronic absorption and ethidium bromide (EB) fluorescene spectroscopy. A quasi- reversible redox wave for the central copper ion from the cyclic voltammograms is shown at a plantium electrode. It has been found that the values of the reduction peak current and apparent diffusion coefficient decreased significantly in the presence of DNA compared with that in the absence of DNA, and the electrochemical reaction resistance values increased, the maximal absorption peaks from absorption spectra are red-shifted and the intensity is weakened. At the same time, [Cu(phen) (H-20) (L-Met)] ~+ can remarkably quench the emission intensity of EB-DNA system. All experimentalsults indicate that the interaction of [Cu(phen) (H-20) ( L-Met)] ~+ with calf thymus DNA is strong and the part intercalation is proved to exist.

Key words: COPPER COMPLEX, PHENANTHROLINE, METHIONINE, INTERACTIONS, VOLTAMMETRY, THYMUS GLAND, FLUOROSPECTROPHOTOMETRY, FLUORESCENCE QUENCHER