Factors limiting protein synthesis by isolated ribosomes

Abstract

The “active” and “inactive” ribosomal systems from peas have been examined with respect to differences between the two systems. Although the two systems differ in their response to varied concentrations of the components of the reaction system, simple adjustment of these concentrations to optimal levels does not bring amino acid incorporation by the “inactive” system up to a level which even approaches that of the “active” system. The ribosomes from the two systems do not seem to differ markedly in stability, and both systems have essentially equal ability to form amini acyl-RNA. However, the two systems differ greatly in their ability to bind amino acyl-RNA to ribosomes, and to transfer amino acid from amino acyl-RNA to ribosomal protein. Experiments with polyuridylate indicate that a lesion in the “inactive” system may be related to the binding of messenger RNA to the ribosome.