Electron transport particles released upon lysis of spheroplasts of Escherichia coli B by Brij 58

Abstract

The non-ionic detergent, Brij 58, has been shown to specifically lyse the cytoplasmic membrane of Escherichia coli. This communication examines the electron transport system in membrane fractions prepared from such lysates and compares this system to those prepared by mechanical procedures. 1. 1. The particulate fraction contained all of the respiratory carriers demonstrable in whole cells in essentially the same ratios although enriched by 3–5-fold over their concentration in whole cells. 2. 2. Succinate, formate, and NADH but not glutamate, malate, or dihydroorotate were actively oxidized by the particulate fraction. 3. 3. With the exception of the formate oxidase system which appeared to utilize a system bypassing flavoprotein and cytochrome b 1, the other enzymatic activities appeared to function primarily through normal electron transport routes. 4. 4. The NADH oxidase and succinoxidase systems were sensitive to inhibition by 2- n-heptyl-4-hydroxyquinoline- N-oxide and antimycin A. The results suggest that these inhibitors function at the level of cytochrome b 1. 5. 5. All three activities were sensitive to complete inhibition by CN −. 6. 6. The results obtained from inhibitor studies coupled with the results obtained from examination of steady state, anaerobic, and chemical reduction of the respiratory pigments permitted a scheme for electron flow to be proposed.