Cytochromes ofAcetobacter pasteurianus NCIB 6428: Reaction with oxygen of cytochromeo in cells,membranes, and nonsedimentable subcellular fractions

Cytochromeo ofAcetobacter pasteurianus NCIB 6428, grown with either vigorous or limiting aeration, was located in both membranes and a fraction nonsedimentable by centrifugation (13.5×10⁶ g min) of a French press extract. In oxygen-limited cells, the reaction with oxygen of the oxidase at low temperatures resembled that inEscherichia coli with respect to the spectrum and formation kinetics of an oxygenated intermediate. Both membranous and nonsedimentable cytochromeso formed this intermediate, but faster and at lower temperatures in the latter. The role of this cytochrome, particularly in the light of other bacterial, soluble, ligand-binding hemoproteins, and the kinetic constraints on its reaction are discussed.