Porphobilinogen (PBG) is an organic compound that occurs in living organisms as an intermediate in the biosynthesis of porphyrins, which include critical substances like hemoglobin and chlorophyll.[1]

Porphobilinogen
Names
Preferred IUPAC name
3-[5-(Aminomethyl)-4-(carboxymethyl)-1H-pyrrol-3-yl]propanoic acid
Identifiers
3D model (JSmol)
ChemSpider
DrugBank
ECHA InfoCard 100.006.970 Edit this at Wikidata
EC Number
  • 207-666-3
MeSH Porphobilinogen
UNII
  • InChI=1S/C10H14N2O4/c11-4-8-7(3-10(15)16)6(5-12-8)1-2-9(13)14/h5,12H,1-4,11H2,(H,13,14)(H,15,16) ☒N
    Key: QSHWIQZFGQKFMA-UHFFFAOYSA-N ☒N
  • InChI=1/C10H14N2O4/c11-4-8-7(3-10(15)16)6(5-12-8)1-2-9(13)14/h5,12H,1-4,11H2,(H,13,14)(H,15,16)
    Key: QSHWIQZFGQKFMA-UHFFFAOYAF
  • C1=C(C(=C(N1)CN)CC(=O)O)CCC(=O)O
Properties
C10H14N2O4
Molar mass 226.229
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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The structure of the molecule can be described as molecule of pyrrole with sidechains substituted for hydrogen atoms at positions 2, 3 and 4 in the ring (1 being the nitrogen atom); respectively, an aminomethyl group −CH2−NH2, an acetic acid (carboxymethyl) group −CH2−COOH, and a propionic acid (carboxyethyl) group −CH2−CH2−COOH.

Biosynthesis

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In the first step of the porphyrin biosynthesis pathway, porphobilinogen is generated from aminolevulinate (ALA) by the enzyme ALA dehydratase.

 

Metabolism

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In the typical porphyrin biosynthesis pathway, four molecules of porphobilinogen are concatenated by carbons 2 and 5 of the pyrrole ring (adjacent to the nitrogen atom) into hydroxymethyl bilane by the enzyme porphobilinogen deaminase, also known as hydroxymethylbilane synthase.

Pathologies

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Acute intermittent porphyria causes an increase in urinary porphobilinogen.[2]

References

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  1. ^ Paul R. Ortiz de Montellano (2008). "Hemes in Biology". Wiley Encyclopedia of Chemical Biology. John Wiley & Sons. doi:10.1002/9780470048672.wecb221. ISBN 978-0470048672.
  2. ^ Aarsand, AK; Petersen PH; Sandberg S (April 2006). "Estimation and application of biological variation of urinary delta-aminolevulinic acid and porphobilinogen in healthy individuals and in patients with acute intermittent porphyria". Clinical Chemistry. 52 (4): 650–656. doi:10.1373/clinchem.2005.060772. PMID 16595824.