An enzyme complex, known as the mitochondrial ATPase or FoF1
ATPase, located in the inner mitochondrial membrane, catalyse the
synthesis of ATP.
This enzyme complex is also called as complex V.
It is proposed that transfer of electron and synthesis of ATP
are associated with a gradient of protons across the inner membrane
of mitochondria.
This mechanism of electrons transfer through the respiratory
chain causes the pumping of protons from the mitochondrial matrix
to the inner mitochondrial membrane cytosol.
This causes a decrease in proton concentration in matrix and a
negative electric field is produced in the matrix.
Thus the synthesis of ATP by ATP synthase is diverted due to
the generated proton motive force.
For the synthesis of each molecule of ATP, atleast 3
protons must pass through the FoF1 complex but the numbers
may vary in certain special circumstances.