An
ATPase is an
enzyme that
catalyzes the decomposition of
ATP into
ADP plus an inorganic
phosphate ion. This
dephosphorylation[?] is widely used in all known forms of life as a mechanism for driving energetically unfavourable reactions; as such, ATPases are rarely dedicated solely to dephosphorylating ATP, but rather couple this reaction to some other reaction and use the ATP dephosphorylation as a source of energy.