The nature of the differential inhibition of polyphenylalanine synthesis in extracts from Artemia salina and rabbit reticulocytes by the Phytolacca americana protein.

The difference in sensitivity of polyphenylalanine synthesis in extracts from Artemia salina and rabbit reticulocytes to inhibition by the Phytolacca americana protein (PAP) has been found to be linked to the source of the supernatant enzyme fraction and not the ribosomes. In the presence of reticulocyte supernatant enzyme fraction polyphenylalanine synthesis in less sensitive to inhibition by PAP than that observed in the presence of A. salina supernatant enzyme fraction. The results suggest that reticulocyte elongation factor 2 is responsible for this effect.