Protoporphyrinogen oxidase
| Protoporphyrinogen oxidase | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 477 amino acids | |
| Secondary to quaternary structure | Homodimer | |
| Cofactor | FAD | |
| Identifier | ||
| Gene name | PPOX | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 1.3.3.4 , oxidoreductase | |
| Response type | Redox reaction | |
| Substrate | Protoporphyrinogen IX + 1.5 O 2 | |
| Products | Protoporphyrin IX + 3H 2 O | |
| Occurrence | ||
| Homology family | PPO | |
| Parent taxon | Creature | |
| Orthologue | ||
| human | House mouse | |
| Entrez | 5498 | 19044 |
| Ensemble | ENSG00000143224 | ENSMUSG00000062729 |
| UniProt | P50336 | P51175 |
| Refseq (mRNA) | NM_000309 | NM_008911 |
| Refseq (protein) | NP_000300 | NP_032937 |
| Gene locus | Chr 1: 161.17 - 161.18 Mb | Chr 1: 171.28 - 171.28 Mb |
| PubMed search | 5498 |
19044
|
The protoporphyrinogen oxidase (PPO) ( gene : PPOX ) is the enzyme that the final common reaction step in the metabolic pathways for the preparation of heme and chlorophyll catalyzed . The PPO occurs in almost all organisms. All eukaryotes have the enzyme in their mitochondria . In humans, PPO is produced in the heart, brain, lungs, placenta, liver, skeletal muscles, kidneys and pancreas. Mutations in PPOX can cause a serious metabolic disease called porphyria variegata .
In plants also exists for mitochondrial also a chloroplastisches isoenzyme. A prokaryotic form of PPO is the enzyme called HemG from gram-positive bacteria , which is not found in gram-negative bacteria.
function
PPO catalyses the six electron - oxidation of protoporphyrinogen IX to protoporphyrin IX by means of a non-covalently bound FAD - cofactor involving molecular oxygen (O 2 ). The substrate is planarized and flavored by removing two hydrogen atoms from the pyrrole nitrogen . The product is the first porphyrin in porphyrin biosynthesis and is made by the insertion of iron (II) ions via ferrochelatase to protohem IX or heme b , by insertion of magnesium ions to magnesioprotoporphyrin IX ( magnesium chelatase ), which is further processed in several steps to chlorophyll .
