Pyrroline-5-carboxylate reductase (P5CR) is a universal housekeeping enzyme that catalyzes the reduction of Delta(1)-pyrroline-5-carboxylate (P5C) to proline using NAD(P)H as the cofactor. The enzymatic cycle between P5C and proline is very important for the regulation of amino acid metabolism, intracellular redox potential, and apoptosis.
Meng, Z., Lou, Z., Liu, Z., Li, M., Zhao, X., Bartlam, M., Rao, Z. (2006) Crystal structure of human pyrroline-5-carboxylate reductase J.Mol.Biol. 359: 1364-1377