Preparation of avian ribosomes with low levels of contaminating elongation factors

The preparation of eukaryotic ribosomes with minimal contaminating activity for assaying of elongation factors usually requires rather extensive procedures [ 1,2]. Recently it was reported that rat liver rough micrcl somes can be dissociated in a medium of high ionic strength into ribosomal and membrane components by reaction of nascent polypeptides with puromycin. The released ribosomal components can be isolated as subunits [3,4]. Earlier it was observed that when E. coli ribosomes were separated into subunits, elongation factor EF-G was quantitatively removed [ 51. It seemed possible that these facts taken together provided the basis of a simplified procedure for the isolation of chicken liver ribosomal subunits exhibiting low levels of elongation factor activity. This was found to be the case, and the results are presented in this paper.