Luminescence quenching effect for the interaction of prulifloxacin with trypsin-Britton-Robinson buffer solution system

Prulifloxacin is a kind of new oral taking antibiotic of fluoroquinolone. Conjugation reaction of prulifloxacin with trypsin in Britton-Robinson buffer solution of pH 7.96 was analyzed by UV-vis spectrophotometry and fluorescence spectrometry. The intrinsic fluorescence of trypsin was strongly quenched by prulifloxacin. This effect was rationalized in terms of a static quenching procedure. The binding parameters have been evaluated by fluorescence quenching methods. Negative values ΔG0 for the formation of prulifloxacin-trypsin complex implied that both hydrogen bonds and hydrophobic interactions might play a significant role in prulifloxacin binding to trypsin. The binding distance deduced from the efficiency of energy transfer was 0.84 nm for prulifloxacin-trypsin. Furthermore, association constants and binding mechanism were successfully derived from the fluorescence spectra. UV-vis detections supported a change in the secondary structure of proteins caused by the interaction of prulifloxacin with trypsin.