5-aminolevulinate dehydratase

5-Aminolevulinate dehydratase (also known as ALAD, ALADH, or porphobilinogen synthase) is an enzyme that in humans is encoded by the ALAD gene. This enzyme is found in the cytoplasm of cells and is involved in the second step of the heme biosynthesis pathway. It catalyzes the condensation of two molecules of 5-aminolevulinic acid (ALA) to form porphobilinogen (PBG).

Function

5-Aminolevulinate dehydratase is a crucial enzyme in the biosynthesis of heme, a vital component of hemoglobin, myoglobin, cytochrome, and other heme-containing proteins. The enzyme catalyzes the condensation of two molecules of ALA to form PBG, a cyclic compound that is the precursor to uroporphyrinogen III, the first cyclic tetrapyrrole in the heme biosynthesis pathway.

Clinical significance

Mutations in the ALAD gene can lead to 5-aminolevulinic acid dehydratase deficiency porphyria, a rare form of porphyria that can cause anemia, neuropathy, and other symptoms. In addition, exposure to lead can inhibit the function of 5-aminolevulinate dehydratase, leading to lead poisoning.

See also

• Heme
• 5-Aminolevulinic acid
• Porphobilinogen
• Porphyria
• Lead poisoning