Study Of The Interaction Between Bovine Serum Albumin And Quinolones By Fluorescence Spectroscopy

As a group of globular proteins, serum albumins（SAs） are the most abundant protein carriers in plasma, as well as the important circulating proteins. By using their lipophilic binding sites, SAs play the key roles in in the storage and transport of many endogenous and exogenous compounds, such as small molecule drugs, in animal and human bodies. Since the the storage and transport of drug mocules are the important base and premise of the medical treatments, researches on the binding mechanisms of drugs and proteins are necessary to ensure the efficiency and security of drug use in animals and humans.By taking advantage of the intrinsic fluorescence of SAs, fluorescence spectroscopy was employed widely in the researches on the binding mechanisms of drugs and SAs in recent years. The results obtained by these researches could provide guidance for the molecular design of new drugs,clinical treatment, drug discovery and pharmacokinetics profiling.In this thesis, the study of the interaction between bovine serum albumin（BSA） and quinolones was carried out by fluorescence spectroscopy, including the following two parts:1. Magnetic Fe₃O₄-core Au-shell nanoparticles（MNPs） were synthesized and employed as the supporters of SA. By utiling an external magnet, the SA bound on the surfaces of MNPs could be separated conveniently and effectively, and the concentration of the free drug, the binding constant and the number of binding sites could be calculated by fluorescence data. As an example, the interaction between BSA and ciprofloxacin was examined, and the binding constant and the number of binding sites were calculated to be 2.055 × 105 L mol-1 and 31.7, respectively. The results demonstrate the capability of the present method for profiling of the interactions between SAs and drugs.2. By employing the synthesized MNPs as the supporters of BSA, the binding constant and the number of binding sites of the interaction between BSA and norfloxacin were calculated to be 1.383 ×105 L mol-1 and 38.8, respectively. The effects of Cu²⁺ and Fe³⁺ ions on the binding of BSA and norfloxacin was investigated by the present method. The results indicate that the binding could be enhanced by Cu²⁺, and could be depressed by Fe³⁺ due to the binding competition between Fe³⁺ and norfloxacin.