Lepock J R, Cheng K H, Campbell S D, Kruuv J
Biophys J. 1983 Dec;44(3):405-12. doi: 10.1016/S0006-3495(83)84314-8.
The correlation time for rotational diffusion (tau R) of 2,2,6,6-tetramethyl-4-piperidone-N-oxide (TEMPONE) in Chinese hamster lung (V79) cells has been measured. For these cells in an isosmotic solution at 20 degrees C, tau R = 4.18 X 10(-11) s, approximately 3.6 times greater than tau R = 1.17 X 10(-11) s in water. The relationship between tau R and viscosity was investigated in a number of glycerol-water (0-50%) and sucrose-water (20-40%) solutions and a constant Stokes-Einstein volume of 44 A3 was found for TEMPONE in solutions of less than 20% glycerol and sucrose. This gives an average shear viscosity (for rotation of a small molecule) of 0.038 poise for the cytoplasm. When nonsecular terms were used in the calculation of tau R, the activation energies for rotation of TEMPONE in the above solutions correlated well with the activation energies for shear viscosity. The viscosity increases as the cell is shrunk in hypertonic solutions. It also increases with decreasing temperature with an activation energy of 3.7 kcal/mol, about the same as the activation energy for the viscosity of pure water. The rotational correlation times were carefully calculated considering inhomogeneous line broadening, non-Lorentzian line shapes, the need for accurate tensor values and nonsecular terms.
已测量了2,2,6,6 - 四甲基 - 4 - 哌啶酮 - N - 氧化物（TEMPONE）在中国仓鼠肺（V79）细胞中的旋转扩散相关时间（τR）。对于处于20℃等渗溶液中的这些细胞，τR = 4.18×10⁻¹¹秒，约为其在水中τR = 1.17×10⁻¹¹秒的3.6倍。在多种甘油 - 水（0 - 50%）和蔗糖 - 水（20 - 40%）溶液中研究了τR与粘度之间的关系，发现对于甘油和蔗糖含量低于20%的溶液，TEMPONE的斯托克斯 - 爱因斯坦体积恒定为44 ų。由此得出细胞质的平均剪切粘度（对于小分子旋转）为0.038泊。当在τR的计算中使用非久期项时，TEMPONE在上述溶液中的旋转活化能与剪切粘度的活化能相关性良好。随着细胞在高渗溶液中收缩，粘度增加。粘度也随温度降低而增加，活化能为3.7千卡/摩尔，与纯水粘度的活化能大致相同。考虑到非均匀线展宽、非洛伦兹线形状、准确张量值的需求以及非久期项，仔细计算了旋转相关时间。
