Porphobilinogen synthase

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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.

Heme synthesis—note that some reactions occur in the cytoplasm and some in the mitochondrion (yellow)

Pathology

Lead poisoning works on the cellular level by binding to this enzyme, rendering it useless.

v • d • e Metabolism: amino acid metabolism - porphyrin enzymes
Porphyrin biosynthesis	initial mitochondrial: Aminolevulinic acid synthase - Porphobilinogen synthase cytosolic: Porphobilinogen deaminase - Uroporphyrinogen III synthase - Uroporphyrinogen III decarboxylase - Coproporphyrinogen III oxidase terminal mitochondrial: Protoporphyrinogen oxidase - Ferrochelatase
Heme breakdown to bile	spleen: Heme oxygenase - Biliverdin reductase liver: UDP-glucuronosyltransferase
see also disorders, intermediates

v • d • e Carbon-oxygen lyases (EC 4.2) (primarily dehydratases)
Carbonic anhydrase - Fumarase - Aconitase - Enolase (Alpha) - 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 hydratase