A terminal oxidase that catalyzes quinol-dependent, Na(+)-independent oxygen uptake. Prefers menadiol over other quinols although ubiquinol was not tested (PubMed:8626304). Generates a proton motive force using protons and electrons from opposite sides of the membrane to generate H(2)O, transferring 1 proton/electron. 2 a ubiquinol + n H(+)(in) + O2 = 2 a ubiquinone + n H(+)(out) + 2 H2O May bind up to 3 heme groups per complex. Inhibited by cyanide; is more sensitive to cyanide than cytochrome bd-I oxidase. Energy metabolism; oxidative phosphorylation. Heterodimer of subunits I and II. Induced when bacterial cultures reach stationary phase; synthesis is triggered by phosphate starvation or a shift from aerobic to anaerobic conditions. The N-terminus is blocked. 3-fold decreased ubiquinone levels but no change in redox levels of the ubiquinone pool (in aerobically grown minimal medium with glucose). Belongs to the cytochrome ubiquinol oxidase subunit 1 family. Was originally thought not to translocate protons.