Cu2+、Zn2+和 Pb2+对绿原酸与牛血清白蛋白结合作用的影响

摘要

以杜仲绿原酸（CA）为原料，在模拟人体生理条件下，采用荧光光谱和紫外吸收光谱等方法，考察 Cu2+、Zn2+和 Pb2+对 CA 与牛血清白蛋白（BSA）相互作用产生的影响。结果表明，金属离子的存在不会改变 CA 对 BSA的猝灭类型，但对其猝灭速率常数（kq ）、结合常数（K）以及结合位点（n）会有不同程度的影响；CA 与 BSA 之间的反应属于自发型，主要以范德华力和氢键为主，Zn2+和 Pb2+的存在不会改变其作用力类型，Cu2+则会使作用力变为以静电吸引力为主；Zn2+和 Pb2+会将供体与受体之间的结合距离分别减小1.975%和14.07%，Cu2+的干扰使CA 与 BSA 之间的结合距离增大11.58%；同步荧光光谱显示 CA 与 BSA 中的酪氨酸残基和色氨酸残基都有相互作用，三维荧光测定结果进一步表明猝灭剂对 BSA 构象及微环境会引起变化。%Interaction of chlorogenic acid(CA)from Eucommia ulmoides Oliv. with bovine serum albumin (BSA)was explored under simulative physiological conditions accompany with fluorescence spectroscopy and UV-Vis absorption in the absence and presence of Cu2 + ,Zn2 + and Pb2 + . The results indicated that the mold of fluorescence quenching of CA to BSA was not changed in the presence metal ions,but the quenching rate constant(kq ),the binding constants(K)and binding sites(n)were changed in different degrees. The interaction between of CA and BSA was spontaneous and van der waals force together with hydrogen bond played important roles in this binding process,at the same time,the type was not changed in the presence of Zn2 + and Pb2 + . But electrostatic interaction was not negligible in presence of Cu2 + , Zn2 + and Pb2 + decreased the binding distance of CA for BSA by 1. 975% and 14. 07% ,respectively. However,Cu2 + increased the binding distance of CA for BSA by 11. 58% . Interactions of the tryptophan and tyrosine residues with CA have been discovered by synchronous fluorescence spectroscopic. The re-sults of three-dimensional fluorescence spectroscopy revealed that the conformational and micro-environ-ment of BSA were changed owing to the presence of quencher.