钝顶螺旋藻C-藻蓝蛋白的稳定性和荧光特性

Stability and Fluorescence Characteristics of C-phycocyanin in Spirulina platensis

摘要:

本文探究了钝顶螺旋藻C-藻蓝蛋白（C-PC）的光谱特性，以及在温度、pH、光照（强度、时间、光源）、蛋白质干扰剂等环境因素下其溶液稳定性及荧光特性的变化规律。实验结果表明，C-PC色泽稳定性与荧光特性均受pH、光照、温度及蛋白质干扰剂等因素影响。其中pH 6~7、温度4~30 ℃，避光条件下C-PC相对稳定，溶液色素保留率与蓝度值b*变化范围小于4.93%；C-PC对光照敏感，其中红、蓝波段光源对其影响最大（p<0.05）；在蛋白质干扰剂的存在下，一定浓度的盐酸胍（≥2 mol/L）、乙醇（≥50%，V/V）、十二烷基硫酸钠SDS（≥0.05%，m/V）均可使C-PC严重变性发生褪色，并使其荧光峰淬灭。相关性分析显示，温度、光照强度引起的C-PC色泽变化与其荧光特征峰值呈显著相关性（p<0.05），但pH或蛋白质干扰剂引起的色泽变化与其荧光特征峰值无显著相关性（p>0.05），表明C-PC荧光特性与其色泽稳定性变化不完全一致。研究结果为C-PC在天然色素、荧光试剂等应用领域或进一步的失稳机理研究提供参考。

Abstract:

In this study, the spectral characteristics of C-phycocyanin (C-PC) from Spirulina platensis were studied, and the changes of its solution stability and fluorescence characteristics under the environmental factors such as temperature, pH, light (intensity, time, light source), protein denaturants. The results showed that the color stability and fluorescence characteristics of C-PC were affected by factors such as pH, light, temperature, and protein denaturants. Under the conditions of dark, pH 6~7, and temperature ranged 4~30 ℃, the pigment retention rate and blue value b* of C-PC solution were less than 4.93%, which has good stability. C-PC was sensitive to light, of which the red and blue band light sources have the greatest influence (p<0.05). In the solution of protein denaturants, certain concentrations of guanidine hydrochloride (≥2 mol/L), ethanol (≥50%, V/V), and sodium lauryl sulfate SDS (≥0.05%, m/V) could make C-PC seriously unstable and discolored, and quenched its fluorescence peak. Correlation analysis showed that the color change of C-PC caused by temperature and light intensity was significantly correlated with the peak of its fluorescence characteristics (p<0.05). However, the color change caused by pH or protein denaturants has no significant correlation with the peak of its fluorescence characteristics (p>0.05), indicating that the fluorescence characteristics of C-PC were not completely consistent with the changes in its color stability. The results provided references for the application of C-PC in natural pigments, fluorescent reagents or further research on the mechanism of instability.