Two sites of oxygen control in induced synthesis of respiratory nitrate reductase in Escherichia coli.

The time course of appearance of respiratory nitrate reductase in Escherichia coli after induction by nitrate was analyzed under different conditions, and the inhibitory effects of oxygen, chloramphenicol, and rifampin were compared. Oxygen appeared to inhibit the synthesis of nitrate reductase at the level of transcription. In addition, the translation or some later steps of enzyme formation were blocked.