camR, a negative regulator locus of the cytochrome P-450cam hydroxylase operon

A 4.27-kilobase insert from a HindIII DNA library of Pseudomonas putida carrying the CAM plasmid allowed coordinate expression of genes camD and camC under control of camR, an upstream regulator. The camC gene specifies cytochrome P-450cam, and camD specifies the 5-exo-alcohol dehydrogenase. A 1.38-kilobase deletion from the insert results in the constitutive expression of genes camC and camD; transformation in trans restores the substrate control, indicating that camR is a negative regulator.