目的 采用荧光光谱法研究有无锆离子（Zr^4＋）共存时槲皮素与人血清白蛋白（HSA）的相互作用。方法 于10 mL的比色管中，依次加入0.20 mol/L Tris-HCl缓冲溶液（pH 7.40）2.50 mL，0.10 mol/L NaCl溶液1.0 mL，一定量的HSA溶液，Zr^4＋溶液，槲皮素溶液，用二次蒸馏水定容至10 mL。HSA荧光激发/发射波长为281/352 nm，激发和发射光狭缝宽度为3 nm，在波长300～500 nm内记录荧光光谱。结果 测得了有无锆离子存在时槲皮素-HSA结合反应的平衡常数和结合摩尔位点数分别为1.032×10⁶ L/mol、2.964×10⁵ L/mol，1.13、1.07；确定槲皮素-HSA的作用类型为静态猝灭过程。结论 锆离子、槲皮素对HSA荧光均有猝灭作用，而且二者共存时对HSA荧光有协同猝灭作用，其猝灭机制为槲皮素与锆离子形成配合物后再对HSA的荧光有猝灭作用，而不是槲皮素和锆离子各自猝灭的简单累加。

Objective To study the interactions between quercetin (Qct) and human serum albumin (HSA) with or without zirconium ion (Zr⁴⁺) coexisting by fluorescence spectrometry. Methods A series of solutions, 0.20 mol/L Tris-HCl buffer solution (pH 7.40) 2.50 mL, 0.10 mol/L NaCl solution 1.0 mL, a certain amount of HSA stock solution, Zr⁴⁺ solution, Qct solution, and ddH₂O were successively added into a 10 mL colorimetric tubes. The fluorescence excitation/emission wavelengths of HSA was 281/352 nm, the slit width of excitation/emission was 3 nm, and the fluorescence spectrometry of the solution was scanned from 300 to 500 nm. Results For Qct-Zr⁴⁺-HSA and Qct-HSA, the effective quenching constants (K_a) and binding molar site number were 1.032 × 10⁶ L/mol and 2.964 × 10⁵ L/mol, 1.13 and 1.07, respectively. The interaction between Qct and HSA was static quenching process. Conclusion The results show that both Zr⁴⁺ and Qct have quenching effects on HSA, and coexisting of the both has the synergic quenching effects on HSA. The study on the quenching mechanism reveals that the quenching effects of Qct-Zr⁴⁺ on HSA is due to the complex of Qct and Zr⁴⁺ rather than the simple accumulation of respective quenching of Qct and Zr⁴⁺.

泰安市科技发展计划项目（20120254）