Regulation of the synthesis of catalase and peroxidase in Escherichia coli.

Glucose suppresses the synthesis of catalase and of peroxidase in Escherichia coli. Exhaustion of the glucose present in a complex medium, or abrupt transfer of cells from a glucose-containing to a glucose-free medium, resulted in a sharp increase in both catalase and peroxidase. The glucose effect was diminished by CAMP, added to the suspending medium, thus identifying it as a catabolite repression. Aerobic growth of E. coli compared to anaerobic growth caused a large increase in catalase and peroxidase. This was not dependent upon either 02 or HzOz, since a similar induction was caused by the addition of NOs-, under anaerobic conditions. Mutants defective in the biosynthesis of ubiquinone were also defective in the ability to induce the synthesis of catalase and peroxidase. p-Hydroxybenzoate, which imparts phenotypic normality to these respiratory mutants, restored normal induction of catalase and peroxidase. Catalase and peroxidase were thus co-induced with the components of the respiratory chain. In all cases of induction of peroxidase and catalase, the increase in the former preceded that of the latter. Furthermore, the increase in peroxidase was transitory, whereas catalase increased to a more stable plateau. E. coli can generate two electrophoretically distinct catalases. One of these is constitutive and was present even in anaerobically grown or in glucoserepressed cells, whereas the other appeared only when the synthesis of catalase was derepressed in the absence of glucose by oxygen or nitrate.