Thomas N S, Arnstein H R
Eur J Biochem. 1984 Aug 15;143(1):27-33. doi: 10.1111/j.1432-1033.1984.tb08334.x.
Poly(A)-rich RNA was isolated from rabbit reticulocyte polyribosomes by affinity chromatography on oligo(dT)-cellulose and fractionated in sucrose gradients under non-denaturing conditions. Most of the translatable RNA sedimented in sucrose gradients both as free 9S mRNA and as a 22S complex containing 18S ribosomal RNA and a protein of Mr 66 000. The complex was characterized by identification of the translation products. Experiments with both labelled globin mRNA and Mr-66 000 protein indicate that the complex is not an artefact, but rather that it is formed during the initiation of protein synthesis. The Mr-66 000 protein appears to be a component of the 48S pre-initiation complex and recycles before 80S complex formation.
富含多聚腺苷酸（Poly(A)）的RNA通过在寡聚（dT）-纤维素上进行亲和层析从兔网织红细胞多核糖体中分离出来，并在非变性条件下于蔗糖梯度中分级分离。大部分可翻译的RNA在蔗糖梯度中沉降，既以游离的9S mRNA形式，也以包含18S核糖体RNA和分子量为66000的蛋白质的22S复合物形式。通过鉴定翻译产物对该复合物进行了表征。用标记的珠蛋白mRNA和分子量为66000的蛋白质进行的实验表明，该复合物不是人为产物，而是在蛋白质合成起始过程中形成的。分子量为66000的蛋白质似乎是48S起始前复合物的一个组分，并在80S复合物形成之前循环利用。
