Functional size measurements of the ubiquinol oxidase activity of the cytochrome o terminal oxidase complex of Escherichia coli.

The functional molecular mass for ubiquinol-1 oxidation by the Escherichia coli terminal oxidase, cytochrome o, was determined by radiation-inactivation analysis of membranes from a cytochrome d-deficient mutant. The functional molecular mass for ubiquinol-l oxidase activity was found to be 38.3 +/- 2.65 kDa.