Table 1.
Human enzymes involved in proline metabolism
| Proline oxidase | P5C dehydrogenase | P5C synthetase | P5C reductase | OAT | Prolidase | |
|---|---|---|---|---|---|---|
| EC | EC 1.5.99.8 | EC 1.5.1.12 | None | EC 1.5.1.2 | EC 2.6.1.13 | EC 3.4.13.9 |
| Subcellular location | Mitochondrial inner membrane | Mitochondrial matrix | Mitochondrial inner membrane | Cytoplasm | Mitochondrial matrix | Cytoplasm |
| Subunit size (kDa) | 63 | 62 | 81 | 32 | 49 | 54.3 |
| Structure | Unknown | Homodimer | Hexamer | Homopolymer | Homohexamer | Homodimer |
| Cofactor | Unknown | NAD+ | ATP, NAD(P)H | NAD(P)H | Vitamin B6 | Mn2+,Ca2+, Mg2+,Fe2+ |
| Activity in tissues | Liver, kidney, brain | Ubiquitous | Small intestine mucosa, colon, pancreas, brain, thymus | Ubiquitous | Ubiquitous | Ubiquitous |
| Disease association | HPI | HPII | Hypoprolinemia | Cutis laxa | Gyrate atrophy | Prolidase deficiency |
| Map location | 22q11.21 | 1p36.13 | 10q24.1 | 17q25.3 | 10q26.13 | 19q13.11 |
| Gene/locus MIM | PRODH 606810 | ALDH4A1 606811 | ALDH18A1 138250 | PYCR1 179035 | OAT 613349 | PEPD 613230 |
ALDH, aldehyde dehydrogenase; EC, enzyme commission number; HPI, hyperprolinemia type I; HPII, hyperprolinemia type II; MIM, mendelian inheritance in man; OAT, ornithine aminotransferase; P5C, Δ-1-pyrroline-5-carboxylate; PEPD, peptidase; PRODH, proline dehydrogenase; PYCR1, pyrroline-5-carboxylate reductase 1.