螺旋藻（Spirulina platensis）藻胆体在解离过程中荧光发射光谱和光能传递的研究

对螺旋藻（Ｓｐｉｒｕｌｉｎａｐｌａｔｅｎｓｉｓ）藻胆体在室温和７７Ｋ处于不同浓度磷缓冲溶液和不同解离时间的荧光发射光谱进行了研究。藻胆体在０．９ｍｏｌ／Ｌ磷酸缓冲溶液中，由于没有发生解离，光能传递效率高，在７７Ｋ荧光发射光谱中只有一个峰，位于６８７ｎｍ，属于别藻蓝蛋白－Ｂ。当藻胆体悬浮在０．３ｍｏｌ／Ｌ磷酸缓冲溶液中１分钟，７７Ｋ荧光光谱的主峰出现在６８４ｎｍ．又出现６５５ｎｍ和６６６ｎｍ荧光峰，它们依次属子Ｃ－藻蓝蛋白和别藻蓝蛋白。在２小时；６５５ｎｍ荧先峰成为主峰，６８４ｎｍ荧光峰为次峰，６６６ｎｍ荧光肩消失。这表明Ｃ－藻蓝蛋白所捕获的先能已不能传递给别藻蓝蛋白，但能传给别藻蓝蛋白－Ｂ。我们提出在螺旋藻藻胆体中存在两类Ｃ－藻蓝蛋白，一是与别藻蓝蛋白相连接，另一是与别藻蓝蛋白－Ｂ相连接。

STUDIES ON THE FLUORESCENCE EMISSION SPECTRA AND ENERGY TRANSFER OF PHYCOBILISOMES FROM SPIRULINA PLATENSIS IN THE COURSE OF DISSOCIATION

Fluorescence emission spectra of phycobilisomes from Spriulila platensis in 0.1, 0.3, 0.6 and 0.9 mol/L phosphate buffer at different times of dissociation were studied at room temperature and 77K. There were three bands in 77K fluorescence spectrum of dissociated phycobilisomes: F655,F666 and F687,characteritic respectively of C-phycocyanin(C-PC),allophycocyanin (APC)and allophycocyanin-B (APC-B). But there was only F687 in that of intaCt phycobilisomes (in 0.9 mol/L phosphate buffer).When phycobilisomes Dissociated, F655 appeared before F666. It shoed that the linkage between C-PC and APC was more unstable than that of APC and APC-B.Phycobilisomes in 0.3 mol/L phosphate biber for 1 min, the fluorescence maxima was shifted from 687 um to 684 um. and then F655 appeared and increased rapidly.At 10 min,the main fluorescence peak was located at 684 um F655 continued to increase,and F666 appeared. At 30 min, both F655 and F666 inCreaSed, and the relahve fluorescence of F655 was higher than that of F666 and F684,indication that phycobilisornes dissodated severely.At 2 h,F655 inrmed, F684 decreased,and F666 disappears. It indicatal that the energy rapted by C-PC Couldn't transfer to APC,one links with APC,the other links with APC-B. The phycobiliproteins in phycobilisomes of S. platensis constitute energy transfer chain, shown as follows.Phycobilisiomes in 0.1 mol/L phosphate buffer for 2 h, only C-PC fluorescence emission band was observed. The phycobilisomes dissocated completely,and the energy couldn't tranfer from C-PC iD APC and APC-B.