Studies on the Interchangeability of One of the Mammalian and Bacterial Supernatant Factors in Protein Biosynthesis

The binding of phenylalanyl transfer RNA to polyuridylic acid-charged Novikoff tumor and rabbit reticulocyte ribosomes is stimulated similarly by Escherichia coli transfer factor T and tumor supernatant fraction. When supplemented with mammalian transfer factor T2, bacterial factor T substituted on reticulocyte ribosomes for the corresponding mammalian transfer factor T1 in polymerization of phenylalanyl-tRNA into polyphenylalanine, but E. coli factor G did not replace mammalian T2. In reverse, with E. coli ribosomes, reticulocyte factor T1 did not substitute for bacterial factor T.