DEOXYRIBONUCLEATE SOLUTIONS - SEDIMENTATION IN A DENSITY GRADIENT PARTIAL SPECIFIC VOLUMES DENSITY AND REFRACTIVE INDEX INCREMENTS AND PREFERENTIAL INTERACTIONS
DEOXYRIBONUCLEATE SOLUTIONS - SEDIMENTATION IN A DENSITY GRADIENT PARTIAL SPECIFIC VOLUMES DENSITY AND REFRACTIVE INDEX INCREMENTS AND PREFERENTIAL INTERACTIONS
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DOI：
10.1002/bip.1968.360060805
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发表时间：
1968-01-01
期刊：
影响因子：
2.9
通讯作者：
EISENBER.H
中科院分区：
文献类型：
--
作者：
COHEN, G;EISENBER.H
在较宽的盐浓度范围内测定NaDNA的NaCl溶液和CsDNA的CsCl溶液中的密度增量（[图像][rho]/[图像]C2）[图像];使用小牛胸腺DNA，通过超声辐照片段化至分子量为4-6 x 10^。在25 [degree]C下，NaDNA的部分比容[image]20在水中为0.500 ml/g，CsDNA为0.440 ml/g。这两个值都随着NaCl和CsCl浓度的增加而增加。还测定了各种实验条件下的折射率增量。的密度增量（在恒定的化学势的扩散溶质）的平衡沉降在密度梯度和分子量的评价的相关性进行了讨论。扩散组分的分配系数，有时被称为优先溶剂化或净水合，来自密度增量和部分体积，并与直接的实验结果相比，只要可用，从膜分布和等压蒸馏。考虑了分配系数的热力学意义以及特定分子机制的可能解释。
Density increments ([image][rho]/[image]C2)[image] in solutions of NaDNA in NaCl and CsDNA in CsCl were determined over a wide range of salt concentrations; calf thymus DNA, fragmented by sonic irradiation to a molecular weight of 4-6 x 10^ was used. The partial specific volume [image]20 of NaDNA at 25 [degree]C was found to be 0.500 ml/g in water, and that of CsDNA 0.440 ml/g. Both values increase with increasing NaCl and CsCl concentration. Refractive index increments under various experimental conditions were also determined. The relevance of the density increments (at constant chemical potential of diffusible solutes) to equilibrium sedimentation in a density gradient and the evaluation of molecular weights is discussed. Distribution coefficients of diffusible components, sometimes referred to as preferential solvation or net hydration, were derived from the density increments and partial volumes and compared with direct experimental results, whenever available, from membrane distribution and isopiestic distillation. The thermodynamic significance of the distribution coefficients as well as possible interpretations in terms of specific molecular mechanisms are considered.