Gattoni R, Stevenin J, Jacob M
Nucleic Acids Res. 1977 Nov;4(11):3931-41. doi: 10.1093/nar/4.11.3931.
Metrizamide gradients were tested for the possible fractionation of the constitutive units of nuclear particles. Material from 35-55 S monoparticles was indeed distributed along the gradient but rerun experiments, CsCl density determinations, formaldehyde fixation prior to centrifugation suggested that the separation was due to dissociation or (and) action of endogeneous ribonucleases rather than to monoparticle fractionation. That dissociation had indeed occured was confirmed by the study of 60-110 S polyparticles. They were dissociated into ribonucleoproteins rich in phosphoproteins and into free proteins. These products were essentially similar to those obtained after NaCl treatment of the particles though the modes of action of metrizamide and NaCl are likely to be different. The loss of proteins from particles reaches 60-70% and we conclude that metrizamide gradients are not utilizable for the fractionation of the units of nuclear particles.
对甲泛葡胺梯度进行了测试，以确定其是否可能用于分离核颗粒的组成单位。来自35 - 55S单颗粒的物质确实沿梯度分布，但重复实验、氯化铯密度测定以及离心前的甲醛固定表明，这种分离是由于内源性核糖核酸酶的解离或（和）作用，而不是单颗粒的分级分离。对60 - 110S多颗粒的研究证实确实发生了解离。它们被解离成富含磷蛋白的核糖核蛋白和游离蛋白。这些产物与用氯化钠处理颗粒后得到的产物基本相似，尽管甲泛葡胺和氯化钠的作用方式可能不同。颗粒中蛋白质的损失达到60 - 70%，我们得出结论，甲泛葡胺梯度不适用于核颗粒单位的分级分离。
