Polyribosomes of Escherichia coli. Breakdown during glucose starvation.

Abstract Growing cells incubated in a medium lacking glucose undergo a rapid breakdown of polyribosomes to single 70 S ribosomes. This conversion is accompanied by a loss of protein-synthetic capacity in vivo and is inhibited by chloramphenicol, but not by puromycin. The conversion of polysomes to 70 S ribosomes, with a half-life of 1½ to 2½ min at 37°, appears to reflect a breakdown of messenger ribonucleic acid. The polysomes remaining during starvation remain the most active sites of protein synthesis.