Proton/deuteron passage from F
of ATP synthase in mitochondria. Protons enter the cytoplasmic half-channel and reach Asp61 on subunits c. Protonated Asp61 moves into the lipid bilayer. When protonated Asp61 reaches the matrix half-channel, it is deprotonated by the stator charge of Arg210 on subunit a. A temporary stutter of the rotor is expected during the passage of deuteron. * The ratio of deuterons (D+) to protons (H+) is ~1:15000.