Some ATPases work in reverse, using the energy from the hydrolysis of ATP to create a proton gradient.

There are different types of ATPases, which can differ in function (ATP synthesis and/or hydrolysis), structure (F-, V- and A-ATPases contain rotary motors) and in the type of ions they transport.

The sequential protonation and deprotonation of Asp61 of subunit C is coupled to the stepwise movement of the rotor.

[6] In V-ATPases, there are three proteolipid subunits (c, c′ and c′′) that form part of the proton-conducting pore, each containing a buried glutamic acid residue that is essential for proton transport.

[7][8] In a recent study c-subunit has been indicated as a critical component of the mitochondrial permeability transition pore.