The Investigation of the Interaction between Lomefloxacin and Human Serume Albumin by Specteroscopic Methods


1 Department of Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran

2 Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran


Mechanism of the binding of lomefloxacin (LMF) with human serum albumin has been studied at physiological pH (7.4) using fluorescence spectroscopic technique. LMF is a third-generation fluoroquinolone antibiotic that exhibits striking potency against a broad spectrum of Gram-negative and Gram-positive bacteria through inhibition of DNA gyrase. Lomefloxacin is a drug that is excreted in urine and has very variable systemic absorption. Human serum albumin (HSA) is the most important and abundant constituent of blood plasma and serves as a protein storage component. Recently, the three-dimensional structure of HSA was determined through X-ray crystallographic measurement. Fluorescence studies showed that (LMF) has an ability to quench the intrinsic fluorescence of HSA through a static quenching  procedure  according to the Stern–Volmer equation .LMF showed two types of binding sites, the first having a very high affinity (1/72 ×107M-1) and a secondary binding site with an affinity two orders lower than the primary site. The number of binding sites for complex: HSA-LMF at 280 nm was calculated 1and0.5. The microenvironment of tryptophan and tyrosin residues and more hydrophobic of fluorophores microenvironment were changed and disturbed by the blue shift in maximum wavelength and decreased in fluorescence intensity in the presence of lomefloxacin revealed  decreased polarity of the fluorophores. The binding site for LMF is in a hydrophobic pocket in the sub-domain II A of HSA.


American Society of Microbiology, Washington,
DC, USA, 1993:1-11.
Dufour C. and O. Dangles, 2005. Flavonoid-serum
albumin complexation: determination of
binding complexation: determination of binding
constants and binding sites by fluorescence
spectroscopy," Biochim. Biophys. Acta 1721,
Quan J., F. Jin, T. Sun and X. Zhou, 2007. "Multispectroscopic
study on interaction of bovine
serum albumin with lomefloxacin ââ‚‌“ copper (II)
Complex" International Journal of Biological
Macromolecules, 40, 299-304.
Tang J., N. Lian, X. He and G. Zhang, 2008.
"Investigation of the interaction between
sophoricoside and human serum albumin by
optical spectroscopy and molecular modeling
methods, "J. Mol. Struct. 889 , 408-41.
Xie M. X., M. Long and Y. liu, 2006.
Characterization of the interaction between
human serum albumin and morinââ‚‌œ Biochim.
Biophys. Acta.1760, 1184-1191
Yue Y., Y. Zhang, J. Qin and X. Chen, 2008.
"Study of the interaction between esculetin and
human serum albumin by multi-spectroscopic
method and molecular modeling," J. Mol.
Struct. 888, 25-32.
Zhang G., Q. Que, J. Pan and J. Guo, 2008. "Study
of the interaction between icariin and human
serum albumin by fluorescence spectroscopy,"
J. Mol. Struct., 881, 132-138