Homogenate dioxygenase
| Homogentisate 1,2-dioxygenase | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 445 AS ; 50 kDa | |
| Secondary to quaternary structure | Homohexamer | |
| Cofactor | Fe 2+ | |
| Identifier | ||
| Gene names | HGD ; AKU | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 1.13.11.5 , dioxygenase | |
| Response type | oxidation | |
| Substrate | Homogenate + O 2 | |
| Products | 4-maleyl acetoacetate | |
| Occurrence | ||
| Homology family | Homogenate dioxygenase | |
| Parent taxon | Creature | |
Homogentisate dioxygenase (HGD) is the name for the enzyme that splits homogentisate to 4-maleyl acetoacetate. This reaction step is important for the breakdown of the amino acid tyrosine in the metabolism of all living things. A deficiency in homogentisate dioxygenase leads to alkaptonuria , a metabolic disease , and the cause is always a mutation in the gene that contains the genetic code for the HGD enzyme.
biosynthesis
The greatest amounts of homogentisate dioxygenase are produced in the tissues of the prostate , small and large intestines , kidneys and liver . In humans , the gene coding for the enzyme is located on chromosome 3 , gene locus q21-q23, and comprises 54,100 base pairs with 14 exons . After transcription , a 1,713 base long mRNA is produced and the final protein counts 445 amino acids after translation .
Catalyzed reaction
The reaction enabled by HGD is the iron (II) -dependent ring opening of the homogenate molecule, with the simultaneous transfer of two oxygen atoms. So the enzyme acts as a dioxygenase . There are no similarities to any other enzyme with iron as a cofactor .
