A low-Mr factor isolated from Escherichia coli inhibits eukaryotic in vitro protein synthesis.

The effect of a low-Mr factor, partially purified from E. coli B, was investigated in E. coli, reticulocyte, and wheat germ lysate in vitro protein synthesis systems. Equal concentrations of factor were needed to inhibit protein synthesis in the eukaryotic system as compared to the prokaryotic system. Experiments suggested that the factor inhibits the initiation step in the eukaryotic systems.