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Aminolevulinate dehydratase
Protein ALAD PDB 1e51.png
PDB rendering based on 1e51.
Available structures
PDB Ortholog search: PDBe, RCSB
External IDs OMIM125270 MGI96853 HomoloGene16 ChEMBL: 3126 GeneCards: ALAD Gene
EC number
RNA expression pattern
PBB GE ALAD 218487 at tn.png
PBB GE ALAD 218489 s at tn.png
More reference expression data
Species Human Mouse
Entrez 210 17025
Ensembl ENSG00000148218 ENSMUSG00000028393
UniProt P13716 P10518
RefSeq (mRNA) NM_000031 NM_001276446
RefSeq (protein) NP_000022 NP_001263375
Location (UCSC) Chr 9:
116.15 – 116.16 Mb
Chr 4:
62.51 – 62.52 Mb
PubMed search [1] [2]

Delta-aminolevulinic acid dehydratase is an enzyme that in humans is encoded by the ALAD gene.[1][2]

The ALAD enzyme is composed of 8 identical subunits and catalyzes the condensation of 2 molecules of delta-aminolevulinate to form porphobilinogen (a precursor of heme, cytochromes and other hemoproteins). ALAD catalyzes the second step in the porphyrin and heme biosynthetic pathway; zinc is essential for enzymatic activity. ALAD enzymatic activity is inhibited by lead and a defect in the ALAD structural gene can cause increased sensitivity to lead poisoning and acute hepatic porphyria. Alternatively spliced transcript variants encoding different isoforms have been identified.[3]


  1. ^ Eiberg H, Mohr J, Nielsen LS (Jun 1983). "delta-Aminolevulinatedehydrase: synteny with ABO-AK1-ORM (and assignment to chromosome 9)". Clin Genet 23 (2): 150–4. doi:10.1111/j.1399-0004.1983.tb01864.x. PMID 6839527. 
  2. ^ Beaumont C, Foubert C, Grandchamp B, Weil D, Van Cong N'Guyen, Gross MS, Nordmann Y (Aug 1984). "Assignment of the human gene for delta aminolevulinate dehydrase to chromosome 9 by somatic cell hybridization and specific enzyme immunoassay". Ann Hum Genet 48 (Pt 2): 153–9. doi:10.1111/j.1469-1809.1984.tb01010.x. PMID 6378062. 
  3. ^ "Entrez Gene: ALAD aminolevulinate, delta-, dehydratase". 

Further reading[edit]