[通过聚（U）及其盐的无盐溶液的电导率测量得到的电荷密度、大离子迁移率和磷酸基团解离常数的结构参数]

[Structural parameters of charge density, macroion mobility and dissociation constants of the phosphate groups from conductivity measurements of salt free solutions of poly(U) and its salt].

作者信息

Kuznetsov I A, Vorontsova O V, Fabrichnaia O B

出版信息

Mol Biol (Mosk). 1983 Mar-Apr;17(2):392-402.

Abstract

Equivalent conductivity (lambda MeP) was studied for the Li+, Na+, K+, Cs+, NH4+ salts of poly(U) and for polyribouridilic acid. Concentration of the salt free solutions of poly(U) ranges from 1 . 10(-4) M-3 . 10(-3) M. Limiting equivalent conductivity (lambda 0 MeP) was obtained based on linear dependence of lambda MeP on Cp1/2 (where Cp is the concentration of nucleic phosphorus). The lambda 0 MeP values obtained were shown to increase linearly with the increase of the limiting mobility of counterion. These data were used to calculate limiting mobility of macroion (lambda p = 43 Ohm-1 Cm2 equiv-1) and parameter xi = 1.13 which characterizes charge density on a macroion. Linear dependence was shown to take place for poly(U) acid and it's salts in the Ostwald's coordinates; moreover, pK value for the phosphate groups is practically independent of the counterion's nature and equal 1.93 +/- 0.32.

摘要

研究了聚（U）的Li⁺、Na⁺、K⁺、Cs⁺、NH₄⁺盐以及聚核糖核酸的当量电导率（λ MeP）。聚（U）无盐溶液的浓度范围为1×10⁻⁴ M至3×10⁻³ M。基于λ MeP对Cp¹/₂（其中Cp是核酸磷的浓度）的线性关系获得了极限当量电导率（λ₀ MeP）。所获得的λ₀ MeP值显示出随着抗衡离子极限迁移率的增加而线性增加。这些数据用于计算大离子的极限迁移率（λp = 43 Ohm⁻¹ Cm² equiv⁻¹）和表征大离子上电荷密度的参数ξ = 1.13。聚（U）酸及其盐在奥斯特瓦尔德坐标中呈现线性关系；此外，磷酸基团的pK值实际上与抗衡离子的性质无关，等于1.93±0.32。