荧光光谱研究两性表面活性剂CHAPS对钝顶螺旋藻藻胆体的解离作用

用蔗糖密度梯度高速离心的方法分离得到钝顶螺旋藻 (Spirulinaplatensis)的藻胆体 ,其室温荧光发射峰位于 6 71nm。以室温荧光光谱为表征研究了离子强度及两性表面活性剂CHAPS对藻胆体稳定性的影响。在 1mol·L-1的磷酸缓冲液中 ,藻胆体的稳定性强 ,7d内藻胆体的室温荧光发射峰位置没有变化。当用水稀释磷酸缓冲液浓度为 0 1mol·L-1,1h后藻胆体溶液的室温荧光发射峰即蓝移至 6 4 8nm ,表明藻胆体已经解离。在低浓度 (<0 6mol·L-1)磷酸缓冲液中 ,藻胆体易解离 ,解离速度随磷酸缓冲液浓度的降低而加快。在磷酸缓冲液浓度为 1mol·L-1的藻胆体的溶液中加入终浓度为 10mmol·L-1的两性表面活性剂CHAPS ,可导致藻胆体的室温荧光发射峰发生蓝移 ,说明CHAPS在高离子强度条件下也可以使藻胆体解离 ,这有利于进一步分离组成藻胆体的各种亚结构

Effect of CHAPS on the Stability of Spirulina Platensis Phycobilisomes

The Spirulina platensis phycobilisomes were isolated by sucrose density gradients ultracentrifugation, and the fluorescence emission maximum of the phycobilisomes at room temperature was at 671 nm. The effects of ionic strength and the zwitterionic detergent CHAPS on the stability of the Spirulina platensis phycobilisomes were studied by room temperature fluorescence spectrum. The phycobilisomes were stable in 1.0 mol x L(-1) phosphate buffer solution, and their fluorescence emission maximum could remain unchanged for 7 days. The fluorescence emission maximum of phycobilisomes was blue-shifted to 648 nm when the concentration of the phosphate buffer solution was diluted to 0.1 mol x L(-1) with deionized water, which suggested that the phycobilisomes had been dissociated. The phycobilisomes were readily dissociated in phosphate buffer solutions of low concentrations (< 0.6 mol x L(-1)) and the speed of the dissociation increased with decreasing the concentration of the phosphate buffer solution. The fluorescence emission maximum of the phycobilisomes in 1.0 mol x L(-1) phosphate buffer solution was blue-shifted to 648 nm when 10 mmol x L(-1) CHAPS was added into the phycobilisomes solution, suggesting that CHAPS could dissociate phycobilisomes under high ionic strength conditions. The results might be useful for isolating intact substructures of phycobilisomes.