SERS光谱研究银离子诱导葡萄糖氧化酶结构变化

Study on Silver Ion-Induced Structural Changes of Glucose Oxidase Based on SERS Spectroscopy

重金属离子的毒性通常是指其与蛋白质(尤其是各种不同的具有生物催化活性的酶)或核酸的相互作用。本研究利用表面增强拉曼(SERS)光谱技术探讨银离子与葡萄糖氧化酶(GOX)的相互作用。黄素腺嘌呤二核苷酸(FAD)是GOX中对其SERS信号产生贡献的部分,通过对比Ag+-GOX和Ag+-FAD混合物的SERS光谱,证实了Ag+是与GOX中的辅酶因子FAD发生了相互作用。进而通过比较GOX与Ag+-GOX的SERS光谱图,推断出Ag+在FAD中N-5和C-4上的羰基氧之间形成了配位键,这项研究为分析重金属离子与蛋白质的相互作用提供了可靠的依据,具有非常重要的生命科学意义。

Heavy metal ion poisoning refers that it can alter the antioxidant balance and bind to sulfhydryl groups or other ligands in life-related species,which inhibits glutathione metabolism and functions of numerous enzymes and hormones.We used Ag+ions as an example to study its interaction with glucose oxidase(GOX)by surface-enhanced Raman spectroscopy.FAD is the SERS-active component of GOX which contributes to the SERS signal.The SERS spectra of the Ag+-GOX complex and Ag+-FAD at the same pH were compared and similar spectral changes were observed for these two complexes,indicating that Ag+combined with the FAD chromophore of GOX.In addition,the SERS spectra of GOX before and after combining with Ag+confirmed that the interaction of Ag+and GOX was from the coordination bonds located between N-5and the carbonyl oxygen lying in C-4.The study indicates SERS is a suitable tool for the in situ determination of protein-metal ion interaction.