Kinetic characterization of the membrane bound cytochromes of Escherichia coli grown under a variety of conditions by using a stopped flow dual wavelength spectrophotometer

Abstract

A study was made of the rapid oxidation kinetics of the cytochromes of E. coli. The b type cytochromes were kinetically heterogeneous, with one species (presumably cytochrome o) oxidized so rapidly that it could fully support observed oxidation rates. Cytochrome d but not cytochrome a1 was also kinetically competent to support respiration. However, in cells grown anaerobically in the presence of NO3-, cytochrome d exhibited slow oxidation kinetics and a red shift in its reduced minus oxidized difference spectrum.