The Effect of Iron Deficiency on Respiration and Energy-coupling in Escherichia coli

Summary: Growth and respiration were affected when iron became limiting in batch cultures of Escherichia coli growing in succinate medium. Decrease occurred in the efficiency with which succinate was converted to bacterial mass, in the respiratory-control ratio, in the extent of stimulation of respiration by silver ions, and in the levels of non-haem iron, cytochrome b 1, and NADH and succinate oxidase activities. On addition of ferric citrate to the iron-limited cultures the above components returned at different rates to the levels found in iron-sufficient bacteria. The efficiency of conversion of succinate to bacterial mass, the respiratory-control ratio, and the concentration of non-haem iron recovered more rapidly than did the level of cytochrome b 1 and the oxidase activities. It is postulated that non-haem iron is involved in respiratory chain-linked energy production.