荧光光谱法研究瑞香黄烷类化合物与牛血清白蛋白的相互作用

在模拟人体生理条件下（pH 7.4）,采用荧光光谱法研究了瑞香黄烷A（DPA）和瑞香黄烷B（DPB）与牛血清白蛋白（BSA）的相互作用。DPA和DPB通过静态猝灭过程使得BSA荧光强度减弱;在25℃下,DPA和DPB与BSA结合常数分别为3.35×106L.mol-1和7.36×106L.mol-1,结合位点数分别为1.073和1.196;通过计算反应热力学参数值,可推断DPA和DPB与BSA作用力主要为氢键或范德华力;根据Foerster非辐射能量转移理论计算DPA和DPB与BSA的结合距离分别为3.11nm和3.04nm;同步荧光光谱法研究表明,DPA和DPB与BSA的结合对蛋白质的构象未产生影响,其结合位点更接近于色氨酸;同时还考察了部分共存金属离子对DPA和DPB与BSA结合作用的影响。

Interaction Between Daphnodorin Compounds and Bovine Serum Albumin by Fluorescence Spectrometry

The interaction between daphnodorin（daphnodorin A,DPA;daphnodorin B,DPB） and bovine serum albumin（BSA） was investigated by fluorescence spectrometry under the simulative physiological conditions（pH 7.4）.The DPA and DPB caused the fluorescence intensity of BSA decreasing through static quenching procedure.At 25℃,the binding constants（KA） and the number of binding sites（n）for DPA and DPB with BSA were calculated to be 3.35×106L·mol-1 and 7.36×106L·mol-1,1.073 and 1.196,respectively.The main binding forces of DPA and DPB to BSA were concluded as hydrogen bonds and Van der Waals forces from the calculated values of the thermodynamic parameter.The binding distances between BSA（donor） and the compounds（acceptor） were determined to be about 3.11nm（DPA） and 3.04nm（DPB） based on Foerster nonradiative energy theory.The interactions between BSA and the tested compounds（DPA and DPB） did not change the conformation of BSA,and the binding sites of compounds to BSA were near tryptophan residues by synchronous fluorescence spectrometry.In addition,the effects of some metal ions on the binding of DPA and DPB with BSA were also studied.