Inhibitors of Protein Biosynthesis

Abstract Emetine is rapidly concentrated from the media by suspension cultures of HeLa cells, and it inhibits protein biosynthesis by 50% at a concentration in the media of 4 x 10-8 m. The synthesis of DNA is partially inhibited by emetine, but the primary effect of the alkaloid in HeLa cells appears to be on the biosynthesis of protein. In contrast to the effects of cycloheximide, the effects of emetine on DNA and protein synthesis are irreversible. Synthesis of host cell RNA is unaffected by emetine, but viral RNA synthesis in poliovirus-infected HeLa cells is inhibited by this drug. Emetine prevents the breakdown of polyribosomes induced by puromycin but does not affect the puromycin-induced release of nascent peptide. The observations reported in this paper provide a biochemical basis for the toxic and therapeutic properties of emetine.