Diffusion Coefficient and Relaxation Time of Aliphatic Spin Probes in a Unique Triglyceride Membrane.
Diffusion Coefficient and Relaxation Time of Aliphatic Spin Probes in a Unique Triglyceride Membrane.
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独特的甘油三酯膜中脂肪族自旋探针的扩散系数和弛豫时间。
DOI：
10.1021/la026813d
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
K. Nakagawa
中科院分区：
文献类型：
--
作者：
K. Nakagawa
用连续波电子顺磁共振(CW EPR)和饱和恢复谱方法研究了脂肪族自旋探针在一种独特的甘油三酯膜中的分子动力学。用慢运动电子顺磁共振波谱模拟得到了不同温度下7-十二烷基硬脂酸、12-十二烷基硬脂酸和16-十二烷基硬脂酸在膜中的旋转扩散系数(R⊥和R∥)。用R-⊥法测得膜中7、12和16-DSA的活化能分别为19±0.9kJ/m ol、24±1.2kJ/m ol和37±1.8kJ/m ol。较高的活化能意味着16-DSA的垂直运动对温度更敏感。随着自旋探针中氮氧基在硬脂链上的进一步下移，电子自旋-晶格弛豫时间(T1e)变短。T1e越短，表示探头部分的灵活性越大。随着温度的升高，DSA的T1e变短。测得的T1e与垂直扩散系数基本一致。此外，对于不同的DSA，H2O和D2O溶液之间的T1e没有显著差异。由此可见，空间效应和氮氧基的局域转动迁移率对T1e的获得有影响。
The molecular dynamics of aliphatic spin probes in a unique triglyceride membrane were investigated by continuous wave electron paramagnetic resonance (CW EPR) and saturation recovery spectroscopic methods. Rotational diffusion coefficients (R⊥ and R∥) obtained by a slow-motional EPR spectral simulation for 7-doxylstearic acid (7-DSA), 12-doxylstearic acid (12-DSA), and 16-doxylstearic acid (16-DSA) in the membrane at various temperatures were obtained. The activation energies calculated using R⊥ values for 7-, 12-, and 16-DSA in the membrane were 19 ± 0.9, 24 ± 1.2, and 37 ± 1.8 kJ/mol, respectively. The higher activation energy implies that the perpendicular motion of 16-DSA is more sensitive to temperature. As the nitroxide group of the spin probe was moved further down the stearic chain, electron spin-lattice relaxation times (T1e) became shorter. The shorter T1e indicates more flexibility around the probe moiety. Also, T1e for the DSAs became shorter when the temperature increased. The values of T1e obtained were consistent with perpendicular diffusion coefficients. In addition, no significant difference in T1e between the H2O and the D2O solutions was observed for the different DSAs. Therefore, it is concluded that steric effects and the local rotational mobility of the nitroxide moiety influence the T1e's obtained.
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DOI：
10.1016/s0005-2728(98)00098-x
发表时间：
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DOI：
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发表时间：
1981
期刊：
Biochimica et biophysica acta
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作者：
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DOI：
10.1073/pnas.79.4.1166
发表时间：
1982-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
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作者：
LAI, CS;HOPWOOD, LE;LUKIEWICZ, S
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