大鼠胸腺脱氧核糖核蛋白的结构与性质。溶解性及沉淀作用

Structure and properties of rat thymus deoxyribonucleoprotein. Solubility properties and effects of precipitation.

作者信息

Itzhaki R F

出版信息

Biochem J. 1967 Nov;105(2):741-8. doi: 10.1042/bj1050741.

DOI:10.1042/bj1050741

PMID:5584015

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1198373/

Abstract

Deoxyribonucleoprotein was prepared from rat thymus and was studied chiefly by the method of electric birefringence. The birefringence depends on the electrical and optical properties of the molecules and on their volume; the decay time of birefringence (after the removal of the electric field) depends on molecular length. 2. A comparison was made of the properties of deoxyribonucleoprotein redissolved after precipitation in 0.15m-sodium chloride with those of the original material, the main object being to find if structural changes have occurred in the former. As a preliminary, the dependence of the solubility of the deoxyribonucleoprotein on the concentration of added salt was investigated, and the birefringence properties were also studied after the addition of sodium chloride at low concentrations, after the alteration of pH and after dialysis. 3. It was found that precipitation of deoxyribonucleoprotein occurs in two fractions, beginning at about 0.4mm-sodium chloride. The solubility is minimal at about 0.15m-sodium chloride. 4. The electric birefringence and decay time of the deoxyribonucleoprotein decrease with increasing concentration of added sodium chloride, and the birefringence also decreases after dialysis. Prolonged dialysis leads to precipitation. 5. The properties of deoxyribonucleoprotein redissolved after precipitation with 0.15m-sodium chloride differ considerably from those of the original deoxyribonucleoprotein. This is attributed to some type of disorganization process occurring during precipitation. It is concluded that the organization of the original structure is very specific.

摘要

从大鼠胸腺制备了脱氧核糖核蛋白，并主要用电双折射方法进行研究。双折射取决于分子的电学和光学性质及其体积；双折射的衰减时间（去除电场后）取决于分子长度。2. 对在0.15m氯化钠中沉淀后再溶解的脱氧核糖核蛋白的性质与原始材料的性质进行了比较，主要目的是确定前者是否发生了结构变化。作为初步研究，研究了脱氧核糖核蛋白的溶解度对添加盐浓度的依赖性，还研究了在添加低浓度氯化钠后、改变pH值后以及透析后的双折射性质。3. 发现脱氧核糖核蛋白在约0.4m氯化钠时开始分两部分沉淀。在约0.15m氯化钠时溶解度最小。4. 脱氧核糖核蛋白的电双折射和衰减时间随添加氯化钠浓度的增加而降低，透析后双折射也降低。长时间透析会导致沉淀。5. 用0.15m氯化钠沉淀后再溶解的脱氧核糖核蛋白的性质与原始脱氧核糖核蛋白的性质有很大不同。这归因于沉淀过程中发生的某种类型的无序化过程。得出的结论是，原始结构的组织非常特殊。