PYCR1 is a universal housekeeping enzyme that catalyzes the NAD (P) H-dependent conversion of pyrroline-5-carboxylate to proline. This enzyme may also play a physiologic role in the generation of NADP (+) in some cell types. It forms a homopolymer and localizes to the mitochondrion. Defects in PYCR1 are the cause of cutis laxa autosomal recessive type 2B (ARCL2B). Recombinant human PYCR1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.