- Porphobilinogen synthase
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porphobilinogen synthase Identifiers EC number 4.2.1.24 CAS number 9036-37-7 Databases IntEnz IntEnz view BRENDA BRENDA entry ExPASy NiceZyme view KEGG KEGG entry MetaCyc metabolic pathway PRIAM profile PDB structures RCSB PDB PDBe PDBsum Gene Ontology AmiGO / EGO Search PMC articles PubMed articles Delta-aminolevulinic acid dehydratase Identifiers Symbol ALAD Entrez 210 HUGO 395 OMIM 125270 RefSeq NM_001003945 UniProt P13716 Other data EC number 4.2.1.24 Locus Chr. 9 q32 ALAD 
high resolution crystal structure of a mg2-dependent 5-aminolevulinic acid dehydratase Identifiers Symbol ALAD Pfam PF00490 Pfam clan CL0036 InterPro IPR001731 PROSITE PDOC00153 SCOP 1aw5 Available protein structures: Pfam structures PDB RCSB PDB; PDBe PDBsum structure summary Porphobilinogen synthase (or ALA dehydratase, or aminolevulinate dehydratase) synthesizes porphobilinogen through the asymmetric condensation of two molecules of aminolevulinic acid. All natural tetrapyrroles, including hemes, chlorophylls and vitamin B12, share porphobilinogen as a common precursor.
It is involved in the second step of the metabolism of porphyrin.
Deficiency
A deficiency of porphobilinogen synthase is usually acquired (rather than hereditary) and and can be caused by heavy metal poisoning, especially lead poisoning, as the enzyme is very susceptible to inhibition by heavy metals.[1]
Hereditary insufficiency of porphobilinogen synthase is called porphobilinogen synthase (or ALA dehydratase) deficiency poprhyria. It is an extremely rare cause of porphyria,[2] with less than 10 cases ever reported.[3]
Heme synthesis—note that some reactions occur in the cytoplasm and some in the mitochondrion (yellow)Lead poisoning works on the cellular level by binding to this enzyme, rendering it useless.
References
- ^ ALA dehydratase reaction, from NetBiochem at the University of Utah. Last modified 1/5/95
- ^ Jaffe EK, Stith L (February 2007). "ALAD porphyria is a conformational disease". Am. J. Hum. Genet. 80 (2): 329–37. doi:10.1086/511444. PMC 1785348. PMID 17236137. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1785348. Retrieved 2008-12-10.
- ^ Overview of the Porphyrias at The Porphyrias Consortium (a part of NIH Rare Diseases Clinical Research Network (RDCRN)) Retrieved June 2011
External links
Carbon-oxygen lyases (EC 4.2) (primarily dehydratases) 4.2.1: Hydro-Lyases Carbonic anhydrase - Fumarase - Aconitase - Enolase (Alpha, Enolase 2) - Enoyl-CoA hydratase/3-Hydroxyacyl ACP dehydrase - Methylglutaconyl-CoA hydratase - Tryptophan synthase - Cystathionine beta synthase - Porphobilinogen synthase - 3-isopropylmalate dehydratase - Urocanate hydratase - Uroporphyrinogen III synthase - Nitrile hydratase4.2.2: Acting on polysaccharides 4.2.3: Acting on phosphates 4.2.99: Other B enzm: 1.1/2/3/4/5/6/7/8/10/11/13/14/15-18, 2.1/2/3/4/5/6/7/8, 2.7.10, 2.7.11-12, 3.1/2/3/4/5/6/7, 3.1.3.48, 3.4.21/22/23/24, 4.1/2/3/4/5/6, 5.1/2/3/4/99, 6.1-3/4/5-6 - Genes on chromosome 9
- Lyase stubs
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