Dipartimento di Biochimica "G. Moruzzi," Sezione di Biochimica Farmaceutica, Universitá degli Studi di Bologna, Bologna, Italy.
J Fluoresc. 1996 Sep;6(3):127-38. doi: 10.1007/BF00732052.
The fluorescence properties of the phospholipid derivative,N-[1-(2-naphthol)]-phosphatidylethanolamine (NAPH-PE), have been studied by steady-state and time-resolved fluorescence techniques. The new probe is a naphthol adduct of phosphatidylethanolamine. The emission spectrum of the fluorescent phospholipid depends on the pH and on the proton acceptor concentration as expected for a typical two-state excited-state proton transfer reaction. In ethanol solutions at an apparent pH of 6.7 and in the presence of acetate anion (0.14M), a biexponential decay is obtained from global analysis of the data. The lifetimes,τ 1=3.9 ns andτ 2=6.2 ns. are constant across the spectral region 350-460 nm. The decay-associated spectra and the species-associated spectra reproduce well the profiles reported for a two-state excited-state proton transfer reaction. The fluorescent phospholipid has been incorporated into dimyristoyllecithin and dipalmitoyllecithin vesicles. Although lower proton transfer is found, the reaction appears to be dependent on the gel-to-liquid-crystalline phase transition of the lipid membrane. In addition, the steady-state anisotropy of NAPH-PE measured as a function of temperature trace the phase transition of the two vesicle systems. Thus, it is shown that the physical state of the bilayer affects a reaction which takes place at the membrane surface. In the presence of acetate ions (0.3M), global analysis, performed in terms of fluorescence decay parameters, recovers preexponential coefficients that are consistent with an excited-state proton transfer reaction. The short lifetime drops from 3.9 to 0.44 ns without significant changes of the longer-lifetime component.
磷脂衍生物 N-[1-(2-萘酚)]-磷脂乙醇胺（NAPH-PE）的荧光性质通过稳态和时间分辨荧光技术进行了研究。新探针是磷脂乙醇胺的萘酚加合物。荧光磷脂的发射光谱取决于 pH 值和质子受体浓度，这与典型的两态激发态质子转移反应一致。在乙醇溶液中，表观 pH 值为 6.7，存在乙酸根阴离子（0.14M）时，通过对数据的全局分析得到双指数衰减。寿命，τ 1=3.9 ns 和τ 2=6.2 ns。在 350-460nm 的光谱区域内保持不变。衰减相关光谱和物种相关光谱很好地再现了两态激发态质子转移反应的报告轮廓。荧光磷脂已被掺入二肉豆蔻酰磷脂酰乙醇胺和二月桂酰磷脂酰乙醇胺囊泡中。尽管质子转移较低，但该反应似乎取决于脂质膜的凝胶到液晶相转变。此外，作为温度函数测量的 NAPH-PE 的稳态各向异性追踪两个囊泡系统的相变。因此，表明双层的物理状态影响发生在膜表面的反应。在乙酸根离子（0.3M）存在下，通过荧光衰减参数进行的全局分析恢复了与激发态质子转移反应一致的预指数系数。短寿命从 3.9 降至 0.44 ns，而较长寿命组分没有明显变化。
