Porphobilinogen deaminase
Encyclopedia
Porphobilinogen deaminase (also known as hydroxymethylbilane synthase or uroporphyrinogen I synthase) is an enzyme
involved in the third step of the metabolism of porphyrin
, converting porphobilinogen
into hydroxymethylbilane
. The enzyme has the unique cofactor dipyrromethane. Defective activity of this enzyme can lead to the disorder acute intermittent porphyria
.
Older sources categorize it under .
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
involved in the third step of the metabolism of porphyrin
Porphyrin
Porphyrins are a group of organic compounds, many naturally occurring. One of the best-known porphyrins is heme, the pigment in red blood cells; heme is a cofactor of the protein hemoglobin. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at...
, converting porphobilinogen
Porphobilinogen
Porphobilinogen is a pyrrole involved in porphyrin metabolism.It is generated by aminolevulinate and the enzyme ALA dehydratase. PBG is then converted into hydroxymethyl bilane by the enzyme porphobilinogen deaminase, also known as hydroxymethylbilane synthase.Acute intermittent porphyria causes...
into hydroxymethylbilane
Hydroxymethylbilane
Hydroxymethylbilane , also known as preuroporphyrinogen, is a molecule involved in the metabolism of porphyrin. In the third step, it is generated by the enzyme porphobilinogen deaminase, and in the next step the enzyme uroporphyrinogen III synthase converts it into uroporphyrinogen III.In general,...
. The enzyme has the unique cofactor dipyrromethane. Defective activity of this enzyme can lead to the disorder acute intermittent porphyria
Acute intermittent porphyria
Acute intermittent porphyria is a rare autosomal dominant metabolic disorder affecting the production of heme, the oxygen-binding prosthetic group of hemoglobin. It is characterized by a deficiency of the enzyme porphobilinogen deaminase. Acute intermittent porphyria is the second most common...
.