Ribosomes: Analysis by Cesium Sulfate Gradient Centrifugation

Ribosomes from the cytoplasm of a mammalian tissue, HeLa cells, were partially purified and then concentrated into a zone by prolonged centrifugation in Cs(2)SO(4) solution (density, 1.43 grams per milliliter). Ribosomal preparations treated with bentonite prior to density-gradient centrifugation showed single peaks after centrifugation. Material recovered from the peaks represented aggregates of the original 74S particle.