In enzymology, 1-pyrroline-5-carboxylate dehydrogenase () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are (S)-1-pyrroline-5-carboxylate, nicotinamide adenine dinucleotide (NAD<sup>+</sup>), and water. The starting material is in chemical equilibrium with L-glutamate-5-semialdehyde, which is oxidised to L-glutamic acid, giving reduced NADH, and a proton.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-1-pyrroline-5-carboxylate:NAD<sup>+</sup> oxidoreductase. Other names in common use include delta-1-pyrroline-5-carboxylate dehydrogenase, 1-pyrroline dehydrogenase, pyrroline-5-carboxylate dehydrogenase, pyrroline-5-carboxylic acid dehydrogenase, <small>L</small>-pyrroline-5-carboxylate-NAD<sup>+</sup> oxidoreductase, and 1-pyrroline-5-carboxylate:NAD<sup>+</sup> oxidoreductase. This enzyme participates in glutamate metabolism and arginine and proline metabolism.
As of late 2007, 14 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , , and .
In human, the protein is encoded by ALDH4A1 gene.