In enzymology, a beta-diketone hydrolase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are nonane-4,6-dione and H<sub>2</sub>O, whereas its two products are 2-pentanone and butanoate.
This enzyme belongs to the family of hydrolases, specifically those acting on carbon-carbon bonds in ketonic substances. The systematic name of this enzyme class is nonane-4,6-dione acylhydrolase. This enzyme is also called oxidized PVA hydrolase.
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and .