EC Explorer

7.1.1.7

quinol oxidase (electrogenic, proton-motive force generating)

2 quinol + O_{2[side 2]} + 4 H⁺_{[side 2]} = 2 quinone + 2 H₂O_{[side 2]} + 4 H⁺_{[side 1]} (overall reaction);;(1a) 2 quinol = 2 quinone + 4 H⁺_{[side 1]} + 4 e^- ;;(1b) O_{2[side 2]} + 4 H⁺_{[side 2]} + 4 e^- = 2 H₂O_{[side 2]}

cydAB (gene names), appBC (gene names), cytochrome bd oxidase, cytochrome bd-I oxidase, cytochrome bd-II oxidase, ubiquinol:O₂ oxidoreductase (electrogenic, non H⁺-transporting), ubiquinol oxidase (electrogenic, proton-motive force generating), ubiquinol oxidase (electrogenic, non H⁺-transporting)

quinol:oxygen oxidoreductase (electrogenic, non H⁺-transporting)

This terminal oxidase enzyme is unable to pump protons but generates a proton motive force by transmembrane charge separation resulting from utilizing protons and electrons originating from opposite sides of the membrane to generate water. The bioenergetic efficiency (the number of charges driven across the membrane per electron used to reduce oxygen to water) is 1. The bd-I oxidase from the bacterium Escherichia coli is the predominant respiratory oxygen reductase that functions under microaerophilic conditions in that organism. cf. EC 7.1.1.3, ubiquinol oxidase (H⁺-transporting).

created 2014 as EC 1.10.3.14, modified 2017, transferred 2018 to EC 7.1.1.7, modified 2020