Cytochrome bo(3) ubiquinol terminal oxidase is the component of the aerobic respiratory chain of E.coli that predominates when cells are grown at high aeration. Has proton pump activity across the membrane in addition to electron transfer, pumping 2 protons/electron. Competitively inhibited by piericidin A, non-competitively inhibited by 2-n-heptyl-4-hydroxyquinoline N-oxide, NaN(3) and KCN; 50% inhibition occurs at 2 uM, 2 uM, 15 mM and 10 uM, respectively. Inhibited by Zn(2+) and Cd(2+). Heterooctamer of two A chains, two B chains, two C chains and two D chains. Increased reduction of the ubiquinone pool (in aerobically grown minimal medium with glucose). Belongs to the cytochrome c oxidase subunit 2 family.