PYCR1 is a universal housekeeping enzyme which catalyzes the NAD(P)H-dependent conversion of pyrroline-5-carboxylate to proline. PYCR1 enzyme also takes a physiologic part in the generation of NADP(+) in certain cell types. PYCR1 forms a homopolymer and localizes to the mitochondrion. Mutations in PYCR1 are the source of cutis laxa autosomal recessive type 2B(ARCL2B).