The inhibition by streptomycin of adaptive enzyme formation in mycobacteria.

A number of Mycobacteria oxidize benzoic acid and some can use it as the sole source of carbon (1). Upon addition of benzoic acid to suspensions of washed organisms in the Warburg vessel its oxidation proceeds slowly for 30 to 60 minutes, then very rapidly until about half the amount of oxygen for complete combustion is taken up. The rate then parallels that of the autorespiration. It was thought that this latent period was due to the slow penetration of benzoic acid into the cell. Cells grown with benzoic acid in the medium show, however, a much shorter latent period, and Stanier (2) has presented evidence that benzoic acid and related compounds are oxidized by Pseudomonas jtuorescens after a similar latent period which he attributes to the formation in the non-proliferating cell suspension of the appropriate adaptive enzymes. We have previously shown (1) that streptomycin inhibits the oxidation of benzoic acid by Mycobacteria. This effect might be the result of the inhibition of the benzoic acid oxidase or the inhibition of the formation of the enzyme by the drug. Evidence indicates (3) that the latter explanation is correct. The following contains further quantitative data on the formation of an adaptive enzyme and the effect of streptomycin on this process.