Mitrokhin Iu I, Sizova S T, Rumiantsev Iu M, Shishkov A V, Mitsova I Z, Todorov I N
Izv Akad Nauk Ser Biol. 1995 Mar-Apr(2):185-90.
Polyribosomes isolated from the rat liver in a medium with low ionic strength were irradiated by "hot" tritium atoms under conditions providing for the replacement of the hydrogen atoms located at the surface of polyribosomes by tritium. After fractionation of such polyribosomes, the radioactivity of the obtained fractions was measured and their proportions were calculated for the total surface accessible for the tritium atoms (in %), as well as their specific radioactivity. The material loosely associated with the polyribosomes and containing amino acyl-tRNA-synthetases is more radioactive than rRNA and r-proteins, especially concerning their specific radioactivity. This suggests that the material is organized as individual molecules located on the surface of ribosomes. The specific radioactivity of the RNA-component of this material (tRNA) is twice that of proteins, thus suggesting its surface localization in the composition of loosely associated material. Based on the pattern of labeling of rRNA and r-proteins of the native and preliminarily dissociated polyribosomes, we propose that the material, loosely associated with the polyribosomes, has affinity to both rRNA and r-proteins.
在低离子强度介质中从大鼠肝脏分离出的多核糖体，在能使多核糖体表面的氢原子被氚取代的条件下，用“热”氚原子进行辐照。对这种多核糖体进行分级分离后，测量所得级分的放射性，并计算其在氚原子可及的总表面中所占的比例（以%表示）及其比放射性。与多核糖体松散结合且含有氨酰 - tRNA合成酶的物质比rRNA和r - 蛋白质具有更高的放射性，尤其是就其比放射性而言。这表明该物质是以位于核糖体表面的单个分子形式存在。该物质的RNA组分（tRNA）的比放射性是蛋白质的两倍，这表明它在松散结合物质的组成中位于表面。基于天然和预先解离的多核糖体的rRNA和r - 蛋白质的标记模式，我们提出与多核糖体松散结合的物质对rRNA和r - 蛋白质都具有亲和力。
