Abstract

Interaction of moxifloxacin with bovine serum albumin and effect of the coexistent drugs on the reaction

Author(s): Baosheng Liu, Chao Yang, Xiaona Yan, Jing Wang, Yunkai Lv

The interaction between moxifloxacin (MXFX) and bovine serum albumin (BSA) was investigated at different temperatures by fluorescence spectroscopy. Results showed thatMXFX could quench the intrinsic fluorescence of BSAstrongly, and the quenching mechanismwas a static quenching process with Förester spectroscopy energy transfer. The electrostatic force played an important role on the conjugation reaction between BSA and MXFX. The order of magnitude of binding constants (Ka) was 104, and the number of binding site (n) in the binary systemwas approximately equal to 1. The binding distance (r) was less than 3 nm and the primary binding site for MXFX was located in sub-domain IIA of BSA. Synchronous fluorescence spectra clearly revealed that the microenvironment of amino acid residues and the conformation of BSA were changed during the binding reaction. In addition, the effect of some antibiotics on the binding constant of MXFX with BSA was also studied.