Zhang Yaheng, Dong Lijun, Li Ying, Li Jiazhong, Chen Xingguo
Department of Chemistry, Lanzhou University, Lanzhou, China.
J Fluoresc. 2008 May-Jul;18(3-4):661-70. doi: 10.1007/s10895-008-0347-9. Epub 2008 Feb 23.
The interaction between bergenin and human serum albumin (HSA) in AOT/isooctane/water microemulsions was studied by fluorescence quenching technique in combination with UV absorption spectroscopy, circular dichroism (CD) spectroscopy and dynamic light scattering (DLS) technique. Fluorescence data in omega (o) 20 microemulsions revealed the presence of a binding site of bergenin on HSA and its binding constants (K) were 1.64 x 10(4), 1.44 x 10(4), 1.26 x 10(4) and 1.09 x 10(4) M(-1) at 289, 296, 303, and 310 K, respectively. The binding of bergenin with HSA in microemulsions was stronger than that in buffer solution. The alterations of protein secondary structure in the microemulsions in the absence and presence of bergenin compared with the free form of HSA in buffer were qualitatively and quantitatively analyzed by the evidence from CD spectra. Enthalpy and entropy changes for the reaction were calculated to be -14.45 kJ mol(-1) and 30.76 J mol(-1) K(-1). These results indicated that bergenin bound to HSA mainly by a hydrophobic interaction in microemulsions which was in agreement with the result of the molecular modeling study. The DLS data suggested that HSA may locate at the interface of the microemulsion and bergenin could interact with them.
采用荧光猝灭技术结合紫外吸收光谱、圆二色（CD）光谱和动态光散射（DLS）技术，研究了岩白菜素与人血清白蛋白（HSA）在AOT/异辛烷/水微乳液中的相互作用。ω（o）20微乳液中的荧光数据表明岩白菜素在HSA上存在一个结合位点，其在289、296、303和310 K时的结合常数（K）分别为1.64×10⁴、1.44×10⁴、1.26×10⁴和1.09×10⁴ M⁻¹。岩白菜素与微乳液中HSA的结合强于其在缓冲溶液中的结合。通过CD光谱的证据，定性和定量分析了在不存在和存在岩白菜素的情况下微乳液中蛋白质二级结构与缓冲溶液中游离形式HSA相比的变化。计算得出该反应的焓变和熵变分别为-14.45 kJ mol⁻¹和30.76 J mol⁻¹ K⁻¹。这些结果表明，岩白菜素在微乳液中主要通过疏水相互作用与HSA结合，这与分子模拟研究的结果一致。DLS数据表明，HSA可能位于微乳液的界面，岩白菜素可以与它们相互作用。
