Interaction Of Serum Albumin And The Micro Molecule By Fluorescence Spectrometry

Interaction analysis between molecules is a method investigating the varieties of chemical, physical, biological and molecular biological properties in the interaction process. Interaction analysis can express the information between acceptor and ligand. Interaction between molecules has been extensively studied and focused for many years in life science, also in clinic and environmental science.Due to the important function of protein, the interaction analysis based on protein has been paid much attention. Many theories and methods has been established and applied in interaction analysis. With the development of science and technology, those theories and methods have been developed gradually as well. Equilibrium dialysis, capillary electrophoresis, ultraviolet spectrometry and fluorescence spectrometry are the main methods to investigate the interaction analysis.Serum albumins are the most abundant proteins in plasma. As the major soluble protein constituents of the circulatory system, serum albumins have many physiological functions and play important role in reserving and transporting nutrition for mammals. The most outstanding property of albumins is their ability to reversibly bind with a large variety of endogenous or exogenous ligands. Therefore, the interaction of serum albumins and ligands has been the focus objective. Owing to intrinsic fluorescence of serum albumins, fluorescence spectrometry has been the most popular method to investigate the interaction of serum albumins and ligands, which is efficient, sensitive and convenient.In this paper, several micro molecules, Triton X-100 (TX), Sodium Dodecyl Benzene Sulfonate (SDBS), Sibutramine (SH), Primaquine (PQ), Citalopram (CIT) and trihexyphenidyl (THP), were selected to interact with bovine serum albumin as the interaction systems which were investigated by two different fluorescence spectroscopic methods respectively. The research contents and results of this paper were as following:(1) The limitation and defect of conventional fluorescence spectrometry, in which the serum albumin was detected to supply fluorescence, were indicated based on the theories. It was considered that the conventional fluorescence spectrometry mistook the fluorescent properties from several tryptophan residues as the whole properties of serum albumin. The information from the conventional fluorescence spectrometry could not express the interaction actually and entirely.(2) The modified fluorescence spectrometry which made the micro molecule as fluorescence source was proposed. Comparing with the conventional fluorescence spectrometry, the information from modified method was more reliable and actual.(3) To solve the overlapping fluorescence spectra from an interaction system, which often happens but has been never mentioned and solved before in publications, a novel technique called"fluorescence background subtracting (FBS) method"has been proposed. Through this method, we can acquire available information from those overlapping fluorescence spectra.(4) Several interaction systems, BSA-TX, BSA-SDBS, BSA-SH, BSA-PQ, BSA-CIT and BSA-THP, were investigated by the conventional fluorescence spectrometry and modified fluorescence spectrometry respectively. Great difference has been found between the binding constants respectively based on the two different methods.(5) The interaction systems could be reduced to four types:a. the system where fluorescence of Trp could expresses the properties of BSA;b. the system where fluorescence of Trp could not expresses the properties of BSA;c. the system whose spectra were verlapping and the effective information could be attained by FBS method ;d. the system whose spectra were verlapping and the FBS method was helpless.