In enzymology, a 1-pyrroline-4-hydroxy-2-carboxylate deaminase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 1-pyrroline-4-hydroxy-2-carboxylate and H<sub>2</sub>O, whereas its two products are 2,5-dioxopentanoate and NH<sub>3</sub>.
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amidines. The systematic name of this enzyme class is 1-pyrroline-4-hydroxy-2-carboxylate aminohydrolase (decyclizing). This enzyme is also called HPC deaminase. This enzyme participates in arginine and proline metabolism.