The Effect of Glucose in the Growth Medium on the Succinic Acid Oxidizing System of Escherichia Coli

Abstract

Manometric determinations have been made of the rate of succinate oxidation by washed Escherichia coli cells derived from a glucose-containing medium. Succinate oxidation is initially slow but after 50-60 minutes the rate increases to a steady level. The duration of the lag period is markedly increased by excessive washing of the cells. With minimally washed cells the final activity may be reduced as a result of competitive inhibition due to endogenous substrates. Conditions of suspension preparation must be carefully standardized to obtain maximum activities and reproducible effects. Results obtained indicate that the enzyme system responsible for the oxidation of succinate is formed when Escherichia coli is grown in a glucose medium and that the lag period can be more satisfactorily explained on the basis of a temporary impermeability of the cell to succinate rather than a period of enzyme adaptation.