Abstract: The binding reaction between ofloxacin and bovine lactoferrin(BLf) was studied by fluorescence spectra in dilute aqueous solution. The binding constant K was found to be 9.4×104 L•mol－1 and the binding sits n to be 2.43 by fluorescence quenching method. The binding distance (r=2.93 nm) and energy-transfer efficiency (E=0.253) between ofloxacin and bovine lactoferrin were also obtained according to the mechanism of Förster-type dipole-dipole nonradiative energy-transfer. The effect of ofloxacin on the conformation of bovine lactoferrin was also analyzed using synchronous fluorescence spectroscopy. The interaction between ofloxacin and bovine lactoferrin is quite strong. Ofloxacin can effect the conformation of bovine lactoferrin in some degree.

Key words: Ofloxacin, Bovine lactoferrin, Fluorescence quenching, Energy transfer