Relationships between membrane-bound cytochrome o from Vitreoscilla and that of Escherichia coli

The cytochrome o terminal oxidases from the bacteria Vitreoscilla and Escherichia coli are structurally and functionally related. They have similar optical spectra, both exhibit ubiquinol-1 oxidase activity and are inhibited similarly. Both enzymes contain four subunits by SDS-polyacrylamide gel electrophoresis analysis and contain protoheme IX and Cu2+ prosthetic groups. Antibodies raised against the oxidase purified from E. coli crossreact with the Vitreoscilla oxidase.     

Escherichia coli membrane-bound polyphosphatase]

A complex of polyphosphatase with E. coli membranes has been isolated and studied. It is shown by gel-filtration through G-200 Sephadex and centrifugation in sucrose concentration gradient that about 5% of polyphosphatase total content in cells is bound with the heterogenous fraction containing smooth membranes and the ribosome-membrane complex. On the basis of the data obtained it is suggested that the formation of a complex of polyphosphatase with membranes is a stage of synthesis and secretion of this enzyme to protoplasm.