RESUMEN
<p><b>AIM</b>To study the binding mode of balofloxacin with DNA and evaluate the influence of Mg2+ on the binding between balofloxacin and DNA.</p><p><b>METHODS</b>Fluorescent spectroscopy was used to study the interaction of balofloxacin with DNA and to calculate the thermodynamic constants. UV-Vis spectra, DNA viscosity titration, competition experiment and the effect of dsDNA and ssDNA on the fluorescense intensity were used to identify the binding mode.</p><p><b>RESULTS</b>Balofloxacin interacted with CT-DNA with a quenching constant of (5.43 +/- 0.07) x 10(3) L x mol(-1). The interaction was exothermic with a Van't Hoff enthalply of - 8.03 kJ x mol(-1) x Mg2+ cation could enhance the quenching constant between balofloxacin and DNA.</p><p><b>CONCLUSION</b>Balofloxacin interacted with CT-DNA in the mode of groove binding and Mg2+ could mediate the binding of balofloxacin to DNA.</p>