In enzymology, a proteasome ATPase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are ATP and H<sub>2</sub>O, whereas its two products are ADP and phosphate.
This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides to facilitate cellular and subcellular movement. The systematic name of this enzyme class is ATP phosphohydrolase (polypeptide-degrading).