牛血清白蛋白与不同糖美拉德反应体系的荧光光谱学研究

Characteristic fluorescence of bovine serum albumin and different sugar Maillard reaction systems

中文关键词:  牛血清白蛋白  美拉德反应  三维荧光  同步荧光  蛋白构象

英文关键词:bovine serum albumin  Maillard reaction  three-dimensional fluorescence  synchronous fluorescence  protein conformation

中文摘要:

      目的 本文研究了牛血清白蛋白(bovine serum albumin, BSA)与不同单糖(木糖、葡萄糖、半乳糖)和双糖(乳糖、麦芽糖)美拉德反应体系的荧光特性。方法 首先将BSA与不同糖按摩尔浓度比1:667混合于磷酸盐缓冲溶液(pH 7.4)中, 在50 ℃加热7 d后得到BSA与不同糖的美拉德反应体系; 进一步用三维荧光光谱及同步荧光光谱研究了BSA与不同糖美拉德反应体系的荧光变化。结果 BSA与不同糖美拉德反应体系在三维荧光光谱中产生了一个新的特征荧光峰(λex330~340 nm, λem400~425 nm), 其荧光强度随反应时间的延长逐渐增大。同步荧光光谱(Δλ=15 nm和Δλ=60 nm)的最大发射波长均发生了不同程度的蓝移。三维荧光光谱及同步荧光光谱的变化幅度均与体系美拉德反应进程一致, 即美拉德反应程度由高到低依次为: BSA-Xyl>BSA-Gal>BSA-Glu, BSA-Mal, BSA-Lac。结论 BSA与不同糖美拉德反应体系中出现特征性新的荧光峰及蓝移, 可作为监测美拉德反应进程及BSA构象改变的指标。

英文摘要:

      Objective The characteristic fluorescence of Maillard reaction systems (MRS) of bovine serum albumin (BSA) and different monosaccharides (xylose, glucose, and galactose) and disaccharides (lactose and maltose) were investigated. Methods BSA and different sugar Maillard reaction systems were prepared in phosphate buffer saline (pH 7.4) with a molar ratio of 1:667, and heated at 50 ℃ for 7 days. The fluorescence development of the BSA and sugar MRS were assessed by 3-dimensional fluorescence and synchronous fluorescence. Results The BSA and sugar MRS exhibited the characteristic new fluorescence peaks (λex 330~340 nm, λem 400~425 nm) on 3-dimensional fluorescence spectra, and their fluorescence intensity increased with heating time. The blue shifts of the maximum emission wave lengths occurred on synchronous fluorescences (Δλ=15 nm and Δλ=60 nm). The degree of fluorescence change of both 3-dimensional and synchronous fluorescences were in accordance to the degree of Maillard reaction, in an order of BSA-Xyl>BSA-Gal>BSA-Glu, BSA-Mal, and BSA-Lac. Conclusion Both characteristic fluorescence peak and blue shift occurred during BSA and sugar Maillard reaction, which could be used as the indicators for progress of Maillard reaction and conformation change of BSA.