胭脂红与牛血清白蛋白相互作用的光谱学研究

Spectroscopic Analysis on the Interaction of Ponceau 4R and Bovine Serum Albumin

采用荧光光谱法与紫外光谱法研究胭脂红与牛血清白蛋白(BSA)之间的相互作用。荧光猝灭结果表明:在模拟生理条件(p H=7.4)下,胭脂红对蛋白质的动态猝灭常数为4.54×10^(13)L/(mol·s),属于静态猝灭;298K时其结合常数与结合位点数分别为5.33×10~7L/mol和1.35;热力学参数熵变(ΔH)与焓变(ΔS)均为负数,表明胭脂红与BSA之间的作用力为范德华力和氢键;依据Fster非辐射能量转移理论求得胭脂红与BSA之间的结合距离为3.75 nm,两者之间极有可能发生非辐射能量转移现象,导致荧光猝灭。同步荧光光谱法和三维荧光光谱法试验表明:胭脂红引起BSA分子构象的变化。

The interaction between Ponceau 4R and bovine serum albumin （BSA） was studied by fluorescence spec-trum and UV-vis spectrum. The results indicated that the dynamic quenching constant Kq=4.54×10^13 L/（molos） and it was a static quenching procedure. The binding constant K between Ponceau 4R and BSA was found to be 5.33×10^7/mol and the binding sites value n was 1.35 at 298 K. The negative entropy change （AH） and enthalpy change （AS） revealed that the interaction of Ponceau 4R with BSA was most likely by van der Waals forces and hydrogen bonds. The distance r between Poneeau 4R and BSA was 3.75 nm based on Foster＇s non-radiative energy transfer theory. The results of syn-chronous fluorescence and three-dimensional fluorescence indicated that the conformation of BSA was changed with the addition of Poneeau 4R.