EC                Enzyme                                 

ubiquinol oxidase (H+-transporting);
cytochrome bb3 oxidase;
cytochrome bo oxidase;
cytochrome bd-II oxidase;
ubiquinol:O2 oxidoreductase (H+-transporting)
Acting on diphenols and related substances as donors;
With oxygen as acceptor
BRITE hierarchy
ubiquinol:oxygen oxidoreductase (H+-transporting)
2 ubiquinol + O2 + n H+[side 1] = 2 ubiquinone + 2 H2O + n H+[side 2] [RN:R09504]
ubiquinol [CPD:C00390];
O2 [CPD:C00007];
H+[side 1]
ubiquinone [CPD:C00399];
H2O [CPD:C00001];
H+[side 2]
Contains a dinuclear centre comprising two hemes, or heme and copper. This terminal oxidase enzyme generates proton motive force by two mechanisms: (1) transmembrane charge separation resulting from utilizing protons and electrons originating from opposite sides of the membrane to generate water, and (2) active pumping of protons across the membrane. The bioenergetic efficiency (the number of charges driven across the membrane per electron used to reduce oxygen to water) depends on the enzyme; for example, for the bo3 oxidase it is 2, while for the bd-II oxidase it is 1. cf. EC, ubiquinol oxidase (electrogenic, non H+-transporting).
EC created 2011, modified 2014
1  [PMID:11017202]
Abramson J, Riistama S, Larsson G, Jasaitis A, Svensson-Ek M, Laakkonen L, Puustinen A, Iwata S, Wikstrom M
The structure of the ubiquinol oxidase from Escherichia coli and its ubiquinone binding site.
Nat. Struct. Biol. 7 (2000) 910-7.
2  [PMID:20416270]
Yap LL, Lin MT, Ouyang H, Samoilova RI, Dikanov SA, Gennis RB
The quinone-binding sites of the cytochrome bo3 ubiquinol oxidase from Escherichia coli.
Biochim. Biophys. Acta. 1797 (2010) 1924-32.
3  [PMID:20392690]
Shepherd M, Sanguinetti G, Cook GM, Poole RK
Compensations for diminished terminal oxidase activity in Escherichia coli: cytochrome bd-II-mediated respiration and glutamate metabolism.
J. Biol. Chem. 285 (2010) 18464-72.
4  [PMID:21987791]
Borisov VB, Murali R, Verkhovskaya ML, Bloch DA, Han H, Gennis RB, Verkhovsky MI
Aerobic respiratory chain of Escherichia coli is not allowed to work in fully uncoupled mode.
Proc. Natl. Acad. Sci. U. S. A. 108 (2011) 17320-4.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 

DBGET integrated database retrieval system