光谱法研究血红蛋白与亚硝酸钠的相互作用

Spectral Studies on the Interaction Between Hemoglobin and Sodium Nitrite

采用紫外-可见光谱、荧光光谱、同步荧光光谱和圆二色(CD)光谱等方法研究了人血红蛋白与亚硝酸钠配位反应的光谱学性质。结果表明:血红蛋白与亚硝酸钠配位反应的进行受血红素中心铁原子价态的影响。高铁血红蛋白与亚硝酸钠发生配位反应生成Hb(III)-NaNO2;亚铁血红蛋白与亚硝酸钠反应生成Hb(II)-NaNO2。但是随着时间的推移,Hb(II)-NaNO2配合物逐渐解离,解离出的亚铁血红蛋白逐渐被氧化成高铁血红蛋白,溶液中的亚硝酸钠再与高铁血红蛋白反应,最终生成Hb(III)-NaNO2配合物。此外,荧光光谱、同步荧光光谱和CD数据显示亚硝酸钠的加入改变了血红蛋白氨基酸残基的微环境,且作用点更接近于色氨酸残基位置,而对蛋白质二级结构影响甚微。

The spectroscopic propertises of reaction between hemoglobin and sodium nitrite were investigated by using UV-Vis absorption spectra, fluorescence spectra, synchronous fluorescence spectra and circular dichroism（CD） spectroscopies. The experimental results showed that the coordination reaction between hemoglobin and sodium nitrite related to the center of heme iron atom valence. Hb（III） reacted with sodium nitrite generating Hb（III）-NaNO2 and Hb（II）NO reacted with sodium nitrite generating Hb（II）-NaNO2. As time went on,Hb（II）-NaNO2 dissociated, and then Hb（II） was oxidized gradually to Hb（III）, sodium nitrite reacted with it and generated Hb（III）-NaNO2 in the end. Fluorescence spectrum, synchronous fluorescence spectrum and CD dates all revealed that sodium nitrite changed the microenvironment of Hb amino acid residues, Hb-NaNO2 sites were closer to Try residues, and nearly had no effect on the secondary structure of protein.