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Rotary catalytic mechanism of mitochondrial ATP synthase


(Text in this section adapted from “ATP synthase.” Wikipedia, The Free Encyclopedia. 27 Mar. 2019.)

ATP synthase is an enzyme that creates the energy storage molecule adenosine triphosphate (ATP).

ATP is the most commonly used “energy currency” of cells for all organisms. It is formed from adenosine diphosphate (ADP) and inorganic phosphate (Pi).

The overall reaction catalyzed by ATP synthase is:

  • ADP + Pi + H+out ⇌ ATP + H2O + H+in

The formation of ATP from ADP and Pi is energetically unfavorable and would normally proceed in the reverse direction.

In order to drive this reaction forward, ATP synthase couples ATP synthesis during cellular respiration to an electrochemical gradient created by the difference in proton (H+) concentration across the mitochondrial membrane in eukaryotes or the plasma membrane in bacteria.

Molecular animation of ATP synthase

Here is a three dimensional animation of all the proteins working together in this complex. We see it situated in a lipid bilayer (organelle membrane.)

GIF mitochondrial ATP synthase

Here is another animation of a similar complex.

GIF mitochondrial ATP synthase 2


Rotary catalytic mechanism of mitochondrial ATP synthase

Learning Standards


Biology, Chemistry, Simple machines