In enzymology, a pyrroline-5-carboxylate reductase () is an enzyme that catalyzes the chemical reaction L-proline + NAD(P)+ 1-pyrroline-5-carboxylate + NAD(P)H + H+ The 3 substrates of this enzyme are L-proline, NAD+, and NADP+, whereas its 4 products are 1-pyrroline-5-carboxylate, NADH, NADPH, and H+. 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 L-proline:NAD(P)+ 5-oxidoreductase. Other names in common use include proline oxidase, L-proline oxidase, 1-pyrroline-5-carboxylate reductase, NADPH-L-Delta1-pyrroline carboxylic acid reductase, and L-proline-NAD(P)+ 5-oxidoreductase. This enzyme participates in arginine and proline metabolism. Structural studies As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes , , , , and . Human genes PYCR1, nuclear gene for mitochondrial protein PYCR2, nuclear gene for mitochondrial protein PYCR3 (formerly PYCRL), cytosolic protein References EC 1.5.1 NADPH-dependent enzymes NADH-dependent enzymes Enzymes of known structure