钝顶螺旋藻藻胆体低速离心制备过程的光谱表征

Spectral Analyses During the Isolation Course of Spirulina Platensis Phycobilisomes Using Low-Speed Centrifugation

采用低速离心的简易方法制备钝顶螺旋藻（Spirulina platensis）藻胆体,对每次离心所得藻胆体粗提液进行吸收光谱测定。光谱分析表明藻胆体粗提液经3～4次低速离心（13000rpm）后,紫外吸收峰位于263nm,且在400～450nm有叶绿素的特征吸收,表明藻胆体溶液纯度不高,含微量的Triton X-100及叶绿素。藻胆体溶液经高浓度钾盐沉淀后,其紫外吸收峰由263nm红移至277nm,吸收光谱中也未出现叶绿素的特征吸收峰,说明藻胆蛋白溶液中已不含Triton X-100及叶绿素。所得藻胆体进一步经层析纯化,纯化的藻胆体的室温荧光发射峰为680nm,表明已获得均一性高的完整的藻胆体。

The phycobilisomes were isolated from Spirulina platensis using low-speed centrifugation. The crude phycobilisomes solution extracted by Triton X-100 was centrifugated （13 000 rpm） four times. The centrifugated phycobilisomes solution was spectrally analyzed using absorption spectrum each time. The absorption spectrum showed that the ultraviolet absorption maximum of the phycobilisomes solution was still at 263 nm, and also exhibited the characteristic chlorophyllous absorption in the rang of 400-450 nm after the fourth centrifugation. This indicated that there existed small quantities of Triton X-100 and chlorophyll in the centrifugated phycobilisomes solution. But the ultraviolet absorption maximum was red-shifted to 277 nm and the chlorophyllous absorption was not observed in the absorption spectrum of the phycobilisomes solution obtained by high concentration salt precipitation, which meant that the method of high concentration salt precipitation could effectively remove Triton X-100 and chlorophyll from the phycobilisomes solution. The precipitated phycobilisomes of Spirulina platensis were further purified by using Sepharose CL-6B column chromatography. The fluorescence emission maximum of the purified phycobilisomes at room temperature was at 680 nm, which indicated that the purified phycobilisomes were intact.