Immunological investigation of the distribution of cytochromes related to the two terminal oxidases of Escherichia coli in other gram-negative bacteria

Monospecific antibodies were raised against the two terminal oxidase complexes of the aerobic respiratory chain of Escherichia coli. These are the cytochrome d and cytochrome o complexes. The antibodies were used to check for the occurrence of cross-reactive antigens in membrane preparations from a variety of gram-negative bacteria by rocket immunoelectrophoresis and immunoblotting techniques. With these criteria, proteins closely related to the cytochrome d complex of E. coli appeared to be widely distributed. Among the strains containing cytochrome d-related material were Serratia marcescens, Photobacterium phosphoreum, Salmonella typhimurium, Klebsiella pneumoniae, and Azotobacter vinelandii. The data suggest that the d-type terminal oxidase in many of these strains is associated in a complex with b-type and a₁-type cytochromes, as has been found to be the case in E. coli, K. pneumoniae and S. typhimurium were also shown to have material cross-reactive to the E. coli cytochrome o complex.