Pd(Ⅱ)与还原型辅酶Ⅰ和溶菌酶相互作用的荧光和共振瑞利散射光谱研究

Interactions of Pd(Ⅱ) with Reduced Coenzyme Ⅰ and Lysozyme by Fluorescence and Resonance Rayleigh Scattering Spectra

在弱酸性介质中,Pd(Ⅱ)能分别与还原型辅酶Ⅰ(NADH)和溶菌酶(Lyso)形成1∶1和2∶1的复合物,并导致NADH和Lyso的荧光猝灭,但不能引起共振瑞利散射(RRS)的变化和增强.但是当Pd(Ⅱ)与NADH和Lyso同时作用并形成n(Pd(Ⅱ))∶n(NADH)∶n(Lyso)=2∶2∶1的三元复合物时,不仅能使Lyso的荧光猝灭,而且能引起RRS显著增强并出现最大散射波长位于309 nm附近的RRS光谱.研究了Pd(Ⅱ)-NADH-Lyso反应体系的荧光和RRS光谱特征,适宜的反应条件,探讨了反应机理及Pd(Ⅱ)与NADH和Lyso的结合位点和结合模式,考查了荧光猝灭和RRS增强的原因.当Pd(Ⅱ)和Lyso过量时,散射增强(ΔI)在一定范围内与NADH的质量浓度成正比,对NADH的检出限为5.7 ng/mL(8.6×10-9mol/L).同样当Pd(Ⅱ)和NADH过量时,散射增强(ΔI)在一定范围内与Lyso的质量浓度成正比,检出限为15.1 ng/mL(1.06×10-9mol/L).因此RRS光谱不仅可为研究金属离子与不同生物分子之间的相互作用提供新的信息,而且也为高灵敏度定量测定痕量NADH和Lyso这样的生物分子创造了条件.

In a weak acidic medium, Pd（Ⅱ） can react with reduced coenzyme I （NADH） or lysozyme （Lyso） to form a 1 ： 1 or 2 ： 1 complex, resulting in fluorescence quenching of NADH or Lyso, but it can not lead to the change and enhancement of resonance Rayleigh scattering （RRS）. However, when Pd（Ⅱ） interacts with NADH and Lyso simultaneously to form a ternary complex of n （Pd（Ⅱ）） ： n（NADH） ： n（Lyso）=2 ：2 ： 1, it will not only give rise to fluorescence quenching of Lyso, but also lead to a significant enhance- ment of RRS and the appearance of a new RRS spectrum whose maximum scattering wavelength is located at about 309 nm. In the present study, the spectral characteristics of fluorescence and RRS and the suitable reaction conditions of the Pd（II）-NADH-Lyso system were investigated, the modes were discussed and the reasons of fluorescence quenching and RRS e binding site and the binding nhancement were considered. When Pd（Ⅱ） and Lyso were in excess, the enhanced RRS intensity （AI） was proportional to the concentra- tion of NADH in a certain range and the detection limit（3a） was 5.7 ng/mL （8.6×10^-9 mol/L）. Similarly, when Pd（Ⅱ） and NADH were in excess, the enhanced RRS intensity （AI） was also proportional to the concentration of Lyso in a certain range, with a detection limit（3a） of 15.1 ng/mL （ is thus concluded that RRS spectrum can not only provide new information for th metal ions and different biological molecules, but also create new conditions for high 1.06×10^-9 mol/L）. It e ly interactions between sensitive determination of trace biomolecules such as NADH and Lyso.