Herson D S, Pon C L
J Bacteriol. 1969 Dec;100(3):1350-4. doi: 10.1128/jb.100.3.1350-1354.1969.
If a cell-free extract of Streptococcus faecalis is fractionated by way of a 10 to 70% sucrose gradient, at least three areas are found capable of protein synthesis having a density greater than can be accounted for by association of individual ribosomes. These areas represent distinct "polysome" peaks rather than random distribution of polymers of varied length. They appear to be membrane subunits. In addition there is a further particle with a density of about 150S, incapable of protein synthesis but which is capable of stimulating protein synthesis in some of the larger fractions found by gradient centrifugation.
如果通过10%至70%的蔗糖梯度对粪链球菌的无细胞提取物进行分级分离，会发现至少有三个区域能够进行蛋白质合成，其密度大于单个核糖体结合所能解释的密度。这些区域代表不同的“多核糖体”峰，而不是不同长度聚合物的随机分布。它们似乎是膜亚基。此外，还有另一种密度约为150S的颗粒，它不能进行蛋白质合成，但能够刺激梯度离心法分离出的一些较大组分中的蛋白质合成。
