Study of Reaction Dynamics between Bovine Serum Albumin and Folic Acid by Stopped-Flow/Fluorescence
YE San-xian1, LUO Yun-jing1*, QIAO Shu-liang3, LI Li2, LIU Cai-hong2, SHI Jian-long1, AN Xue-jing1
1. College of Life Science and Bio-engineering, Beijing University of Technology, Beijing 100124, China 2. Chinese Aeademy of Inspection and Quarantine, Beijing 100123, China 3. Baotou Entry-Exit Inspection and Quarantine, Baotou 014010, China
Abstract：As a kind of coenzyme of one-carbon enzymes in vivo, folic acid belongs to B vitamins, which can interact with other vitamins and has great significance for converting among amino acids, dividing growth of cells and protein synthesis reactions. Half-life, concentration and reaction rate constant of drugs are important parameters in pharmacokinetic study. In this paper, by utilizing fluorescence spectrophotometer and stopped-flow spectrum analyzer, reaction kinetic parameters between bovine serum albumin(BSA) and folic acid in a bionic system have been investigated, which provide references for parameters of drug metabolism related to folic acid. By using Stern-Volmer equation dealing with fluorescence quenching experiments data, we concluded that under 25, 30, and 37 ℃, the static quenching constants of folic acid to intrinsic fluorescence from bovine serum albumin were 2.455×1010, 4.900×1010 and 6.427×1010 L·mol-1·s-1 respectively; The results of kinetic reaction rate have shown that the reaction rate of BSA and folic acid are greater than 100 mol·L-1·s-1 at different temperatures, pH and buffering media, illustrating that the quenching mechanism between BSA and folic acid is to form composite static quenching process. Reaction concentration of bovine serum albumin and its initial concentration were equal to the secondary reaction formula, and the correlation coefficient was 0.998 7, while the half-life (t1/2) was 0.059 s at physiological temperature. With the increase of folic acid concentration, the apparent rate constant of this reaction had a linear increasing trend, the BSA fluorescence quenching rate constant catalyzed by folic acid was 3.174×105 mol·L-1·s-1. Furthermore, with different buffer, the apparent rate constant and reaction rate constant of BSA interacting with folic acid were detected to explore the influence on the reaction under physiological medium, which is of great significance to determine the clinical regimen, forecast the efficacy and toxicity of drugs and rational drug.
叶三仙1，罗云敬1*，乔树亮3，李 莉2，刘彩虹2，史建龙1，安学静1 . 停流荧光法研究牛血清白蛋白和叶酸反应动力学 [J]. 光谱学与光谱分析, 2016, 36(01): 134-139.
YE San-xian1, LUO Yun-jing1*, QIAO Shu-liang3, LI Li2, LIU Cai-hong2, SHI Jian-long1, AN Xue-jing1 . Study of Reaction Dynamics between Bovine Serum Albumin and Folic Acid by Stopped-Flow/Fluorescence . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(01): 134-139.
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