A comparative-study on the interaction betweenmoxifloxacin and bovine serum albumin / bovine hemoglobin

Author(s): BaohongChong, BaoshengLiu, Lihui Zhang, YingGuo

The interaction between moxifloxacin (MXFX) andBovine serumalbumin (BSA) orBovine Hemoglobin (BHb)was investigated at different temperatures by fluorescence spectroscopy. Results showed that the quenchingmechanismofMXFXon BSA/BHbwas a static quenching processwithFörester spectroscopy energy transfer. MXFX could bind to protein through electrostatic force especiallyBSA.The order ofmagnitude of binding constants (Ka)was 104, and the number of binding site (n) in the binarysystem was approximatelyequal to 1.The primarybinding site forMXFXwas located atTrp-212 in sub-domain IIA conof BSAand â-37 Tryptophan residue in hydrophobic cavity of BHb, respectively. The binding distance (r) was less than 3 nm. In addition, the values of nHwere slightly less than 1which indicated negative cooperativeness in the interaction ofMXFXwith protein. Synchronous fluorescence spectra clearlyrevealed that the microenvironment of amino acid residues and the conformation of proteinwere changed during the binding reaction.

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