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. Author manuscript; available in PMC: 2013 May 1.
Published in final edited form as: Trends Biochem Sci. 2009 Dec 16;35(5):298–307. doi: 10.1016/j.tibs.2009.11.001

Figure 1. Oxidative phosphorylation and proton leak pathways in mitochondria.

Figure 1

Respiratory substrates are oxidized at mitochondrial respiratory complexes I–IV, leading to the ejection of protons (H+) into the intermembrane space (for diagramatic simplicity, the intermembrane space is depicted as being continuous with the cytosol). This proton electrochemical gradient is consumed by demand pathways via the Fo/F1 ATP synthase to produce ATP or by proton leak pathways, which release energy in the form of heat. Proton leak pathways can be mediated by UCP or by ANT.