Benial A M F, Dhas M K, Ichikawa K, Yamada K, Hyodo F, Jawahar A, Utsumi H
Biofizika. 2015 Jan-Feb;60(1):88-94.
Electron spin resonance (ESR) studies were carried out for 14N-labeled deuterated 3-methoxy-carbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl (MC-PROXYL) and 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidin-1-oxyl (carboxy-PROXYL) in pure water and various concentrations of liposomal solutions by using 300 MHz ESR spectrometer. The ESR parameters such as the line width, hyperfine coupling constant, rotational correlation time, g-factor, partition parameter and permeability were reported for the samples. The line width broadening was observed for MC-PROXYL and carboxy-PROXYL in liposomal solution. The hyperfine coupling constant was observed for both nitroxyl spin probes. The permeable and impermeable nature of nitroxyl spin probes was demonstrated. The rotational correlation time increases with increasing concentration of liposome. The partition parameter increases with increasing concentration of liposome for MC-PROXYL, which indicates that the nitroxyl spin probes diffuse into lipid membrane. The permeability value decreases with increasing concentration of liposome, which reveals an increase in membrane permeability. The peaks corresponding to the lipid phase were observed for MC-PROXYL in liposomal solution, but not resolved for carboxy-PROXYL. These results confirm the permeable and impermeable nature of nitroxyl spin probes.
利用300兆赫电子自旋共振光谱仪，对14N标记的氘代3 - 甲氧基羰基 - 2,2,5,5 - 四甲基吡咯烷 - 1 - 氧基（MC - PROXYL）和3 - 羧基 - 2,2,5,5 - 四甲基 - 1 - 吡咯烷 - 1 - 氧基（羧基 - PROXYL）在纯水和不同浓度的脂质体溶液中进行了电子自旋共振（ESR）研究。报告了样品的ESR参数，如线宽、超精细偶合常数、旋转相关时间、g因子、分配参数和渗透率。在脂质体溶液中观察到MC - PROXYL和羧基 - PROXYL的线宽变宽。两种硝酰自旋探针均观察到超精细偶合常数。证明了硝酰自旋探针的可渗透和不可渗透性质。旋转相关时间随脂质体浓度的增加而增加。对于MC - PROXYL，分配参数随脂质体浓度的增加而增加，这表明硝酰自旋探针扩散到脂质膜中。渗透率值随脂质体浓度的增加而降低，这表明膜通透性增加。在脂质体溶液中观察到MC - PROXYL对应脂质相的峰，但羧基 - PROXYL未分辨出该峰。这些结果证实了硝酰自旋探针的可渗透和不可渗透性质。
