Electron transport in mutants of Escherichia coli deficient in their ability to synthesize adenosine 3':5'-cyclic monophosphate and the catabolite-gene activator protein.

showed no respiration due to endogenous substrates. Only L-ascorbate with NNN‘N’tetramethyl-p-phenylenediamine was oxidized by membrane particles and the specific activity obtained was lower than in corresponding particles prepared from NH4+-grown cells. Low-temperature reduced-minus-oxidized difference spectra (Fig. 1, trace b) suggested that this lack of electron-transport activity may be due, in part, to a marked decrease in synthesis of several cytochromes.