MITOMYCIN C: EFFECT ON RIBOSOMES OF ESCHERICHIA COLI.

Sucrose-gradient analyses of cell-free extracts of Escherichia coli B show that the sedimentation patterns are markedly affected by exposure of the cells to mitomycin C; 50S subunits are progressively degraded in the cells after 30 minutes exposure. The 30S subunits, although affected, are less sensitive to the antibiotic than the 50S subunits. Incorporation of uracil-2-C(14) into the ribosomal particles by the treated cells is markedly reduced by exposure.