James D R, Turnbull J R, Wagner B D, Ware W R, Petersen N O
Department of Chemistry, University of Western Ontario, London, Canada.
Biochemistry. 1987 Sep 22;26(19):6272-7. doi: 10.1021/bi00393a047.
Analysis of fluorescence decay data for probes incorporated into model or biological membranes invariably requires fitting to more than one decay time even though the same probe exhibits nearly single-exponential decay in solution. The parinaric acids (cis and trans) are examples of this. Data are presented for both parinaric acid isomers in dimyristoylphosphatidylcholine membranes collected to higher precision than normally encountered, and the fluorescence decays are shown to be best described by a smooth distribution of decay times rather than by a few discrete lifetimes. The temperature dependence of the fluorescence decay reveals a clear shift in the distribution to longer lifetimes associated with the membrane phase transition at 23.5 degrees C. The physical significance is that fluorescence lifetime measurements appear to reflect a physical process with a distribution of lifetimes rather than several distinct physical processes.
对掺入模型膜或生物膜中的探针的荧光衰减数据进行分析时，即便同一探针在溶液中呈现出近乎单指数衰减的情况，通常也需要拟合多个衰减时间。顺式和反式十八碳四烯酸就是这样的例子。本文给出了在二肉豆蔻酰磷脂酰胆碱膜中两种十八碳四烯酸异构体的数据，其采集精度高于通常情况，结果表明荧光衰减最好用衰减时间的平滑分布来描述，而非几个离散的寿命。荧光衰减的温度依赖性显示，在23.5摄氏度的膜相变时，分布明显向更长寿命偏移。其物理意义在于，荧光寿命测量似乎反映的是一个具有寿命分布的物理过程，而非几个不同的物理过程。
