Measurement of binding of chloramphenicol by intact cells.

The binding of chloramphenicol to intracellular components of intact cells was measured by procedures based on a silicone-wash technique. The number of stereospecifically bound molecules of chloramphenicol increased with external concentration to a saturation value equal to the number of ribosomes per cell. Chloramphenicol is therefore believed to be attached stereospecifically by a weak bond, most probably to a single site on the 50S ribosome. This bond was found to be temperature-dependent and appeared to be responsible for inhibition of protein synthesis.