Purification of Peptidyl Transfer Ribonucleic Acid from Rabbit Reticulocyte Ribosomes

A purification scheme for peptidyl transfer RNA has been developed using rabbit reticulocyte ribosomes as the starting material. Completed and released (from tRNA) globin chains are rigidly excluded. Ribosomal RNA and ribosomal proteins are also removed. The procedure has also been successfully applied to Escherichia coli and rat liver ribosomes and may have general applicability for the preparation of peptidyl-tRNA from a number of ribosomal sources. The method consists of treatment of ribosomes with LiCl to precipitate rRNA, removal of the LiCl by gel filtration, and ion exchange purification on diethylaminoethylcellulose. Urea is present in all steps, and the pH is maintained on the acid side of neutrality to protect the ester bond between the tRNA and the peptide. A Sephadex G-200 column run in the presence of sodium lauryl sulfate is used to detect the peptidyl-tRNA. Initial studies of the peptides released from rabbit reticulocyte peptidyl-tRNA indicate the presence of completed globin chains bound to the ribosomes as globyl-tRNA.