Interaction Of Four Classes Of Nitrogenous Fused Ring Micromolecule And Bovine Serum Albumin By Spectroscopic Methodology

Protein is the most abundant biomacromolecule in vito, at the same time, it’s the fundamental material which can express all kinds of biological function. As the most abundant in the plasma, serum albumin(SA), the representative of the protein, it plays an vital role in the transportation and storage of drugs. For the reason that bovine serum albumin(BSA) is very similar with human serum albumin(HSA) on strcture and function, BSA always be choose as the object of the research. The interaction between nitrogenous fused ring micromolecules and bovine serum albumin(BSA) was explored by spectroscopy under imitated physiological conditions. The following are the four mian parts of the thesis:1. The study of the interaction between bovine serum albumin and novel spiro[cyclopropane-pyrrolizin](NSCP) has been investigated by spectroscopy. The results showed that NSCP can quench the intrinsic fluorescence of BSA and the quenching mechanism was static. The binding ability of different substituents of BSA can be obtained by the the data of binding constants. The main force between NSCP and BSA can be confirmed through the thermodynamic parameters based on the Van’t Hoff equation.2. The study of the quenching mechanism between carbonyl fused N-confused porphyrin(CF-NCP) to BSA was investigated at 298, 304 and 310 K. After analyzing the fluorescence quenching data according to Stern-Volmer equation, we found that BSA had reacted with CF-NCP and formed a certain new compound. The quenching belonged to static fluorescence quenching, The binding constants(KA) and binding sides(n) were obtained by the improved double logarithm equation. The magnitude of n approximately to 1, which indicated that BSA-(CF-NCP) complex was formed with the molar ratio of 1:1 and there exists a strong binding ability between CF-NCP and BSA.3. The conjugation between BSA and Phacolysin(PCL) was investigated here, using fluorescence spectroscopy, ultraviolet-visible spectroscopy and circular dichroism spectroscopy. The binding constants(KA) and distance(r) of PCL and BSA were calculated respectively, according to Stern-Volmer equation and F?rster non-radiation energy transfer theory. The main conjugation force was estimated by the calculation of thermodynamic parameters and it indicated that hydrogen bonding and van der waals were the main forces. What’s more, both synchronous fluorescence and circular dichroism spectra confirmed conformational changes of BSA.4. The effects of Besifloxacin(BFLX) on BSA fluorescence spectral characteristics were studied with spectroscopy under simulated physiological conditions. The results showed that BFLX can quench the fluorescence intensity of BSA. In the experimental concentration and temperature range, BFLX and BSA could combine to form a complex accord to static quenching characteristics. The thermodynamic parameters indicated that static electricity was the main force to stabilize the complex, the resulting data can provide important information for the pharmacological and biological effects of BFLX and the influence of BFLX on the conformation of protein.