Chen J L, Wildman S G
Science. 1967 Mar 10;155(3767):1271-3. doi: 10.1126/science.155.3767.1271.
Incubation of isolated to bacco chloroplasts with ingredients re quired for protein synthesis resulted in liberation of 70S ribosomnes and poly ribosomes that no longer sedimented with the chloroplasts. With increasing time of incubation, polyribosomes broke down to 70S monosomes. Similarly, microgram quantities of ribonuclease caused chloroplast polyribosomes to break down into monosomes. Both polyribosomes and 70S ribosomes that were isolated on sucrose density gra dients and tested separately in cell-free systems were capable of protein syn thesis; however, polyribosomes formed more protein per unit of RNA than monosomes did.
将分离出的烟草叶绿体与蛋白质合成所需成分一起温育，导致70S核糖体和多核糖体释放出来，它们不再与叶绿体一起沉降。随着温育时间的增加，多核糖体分解为70S单体。同样，微克量的核糖核酸酶导致叶绿体多核糖体分解为单体。在蔗糖密度梯度上分离并在无细胞系统中分别测试的多核糖体和70S核糖体都能够进行蛋白质合成；然而，多核糖体每单位RNA比单体合成更多的蛋白质。
