Terminal oxidations in Bacillus brevis. II. The electron transport system of Bacillus brevis.

Abstract

1. This work characterizes the membrane-bound electron-transport system of Bacillus brevis under conditions of growth where tyrothricin is produced. Cytochrome a603, b559, c551 and a cytochrome o are present as well as flavoprotein and a menaquinone. 2. The electron-transport system possesses NADH, NADPH and succinate oxidase activities. Inhibitor studies show that the electron-transport system is incompletely inhibited by reagents which are known inhibitors of the mitochondrial electron-transport system. 3. NADH oxidase activity is inhibited by commercial tyrocidine and tyrothricin and by tyrothricin isolated from B. brevis grown under identical conditions as those required for the preparation of the electron-transport system. 4. Considering the above findings, the significance of the electron-transport system in growing cells of B. brevis is discussed.