Abstract：
R-phycoerythrin (R-PE) is the most abundant, naturally occurring phycobiliproteins found in red algae. The spectroscopic and structural properties of phycobiliproteins exhibit unique absorption characteristics with two significant absorption maxima at 498 and 565 nm, indicating two different chromophores of R-PE, phycourobilin and phycoerythrobilin respectively. This study aimed to clarify how the stability of R-PE purified from F. lumbricalis was affected by different purification strategies. Crude extracts were compared to R-PE purified by i) microfiltration, ii) ultrafiltration, and iii) multi-step ammonium sulphate precipitation followed by dialysis. The stability of the different R-PE preparations was evaluated with respect to pH (2, 4, 6, 7, 8, 10 and 12) and temperature (20, 40, 60, 80 and 100 °C). The absorbance spectra indicated higher stability of phycourobilin as compared to phycoerythrobilin for heat and pH stability in the samples. All preparations of R-PE showed heat stability till 40 °C from the findings of color, concentration of R-PE and fluorescence emission. The crude extract showed stability from pH 6 to 8, whereas R-PE purified by ultrafiltration and multi-step ammonium sulphate precipitation were both stable from pH 4 to 8 and R-PE purified by microfiltration exhibited stability from pH 4 to 10 from the results of color, SDS-PAGE, and concentration of R-PE. At pH 2, the color changed to violet whereas a yellow color was observed at pH 12 in the samples along with the precipitation of the protein.
摘要：
R-藻红蛋白(R-PE)是最丰富的,在红藻中发现的天然存在的藻胆蛋白。藻胆蛋白的光谱和结构特性表现出独特的吸收特性，在498和565nm处具有两个显着的吸收最大值，指示R-PE的两种不同发色团，分别是藻胆素和藻胆素。本研究旨在阐明不同纯化策略如何影响从龙黄曲霉中纯化的R-PE的稳定性。将粗提取物与通过i)微滤纯化的R-PE进行比较，ii)超滤，和iii)多步骤硫酸铵沉淀,然后透析。在pH(2、4、6、7、8、10和12)和温度(20、40、60、80和100°C)方面评价不同R-PE制剂的稳定性。吸收光谱表明，对于样品中的热和pH稳定性，与藻赤胆素相比，藻香豆素的稳定性更高。从颜色的发现到40°C，所有R-PE制剂都显示出热稳定性，R-PE浓度和荧光发射。粗提物在pH为6至8时显示出稳定性，而通过超滤和多步骤硫酸铵沉淀纯化的R-PE在pH为4至8时都是稳定的，通过微滤纯化的R-PE在pH为4至10时显示出稳定性。SDS-PAGE,和R-PE的浓度。在pH2下,随着蛋白质的沉淀,样品中的颜色变为紫色,而在pH12下观察到黄色。
