[Factors regulating protein synthesis by rabbit reticulocyte ribosomes: variations in their concentrations during cell maturation].

An activator as well as an inhibitor of protein synthesis, were isolated from rabbit reticulocyte ribosomes. The ribosomes of the erythrocytes are inactive in protein synthesis and lacked the activator. However, when the activator moiety was added to the erythrocyte ribosomes, there was a significant increase in their capacity for protein synthesis, provided these ribosomes were freed of their inhibitor by washing beforehand with a detergent.