Porphobilinogen

Porphobilinogen

Names
Preferred IUPAC name 3-[5-(Aminomethyl)-4-(carboxymethyl)-1H-pyrrol-3-yl]propanoic acid
Identifiers
CAS Number	487-90-1  Y
3D model (JSmol)	Interactive image
ChemSpider	995  Y
DrugBank	DB02272  Y
ECHA InfoCard	100.006.970
EC Number	207-666-3
MeSH	Porphobilinogen
PubChem CID	1021
UNII	74KHC72QXK  N
CompTox Dashboard (EPA)	DTXSID4060070
InChI 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) Y Key: QSHWIQZFGQKFMA-UHFFFAOYSA-N Y
SMILES C1=C(C(=C(N1)CN)CC(=O)O)CCC(=O)O
Properties
Chemical formula	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). Infobox references

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]

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

In a early step of the porphyrin biosynthesis pathway, porphobilinogen is generated from aminolevulinic acid (ALA) by the enzyme ALA dehydratase. ^[2]

2

 

aminolevulinic acid

 

2 H₂O

 

 

 

porphobilinogen

Metabolism

Next in the pathway towards porphyrins, four molecules of porphobilinogen are combined into hydroxymethyl bilane by the enzyme porphobilinogen deaminase: ^{[2] [3] [4]}

4

 

porphobilinogen

 

H₂O

4 NH₃

 

 

 

hydroxymethylbilane

Pathologies

Acute intermittent porphyria causes an increase in urinary porphobilinogen. ^[5]

References

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. Battersby, Alan R. (2000). "Tetrapyrroles: The pigments of life". Natural Product Reports. 17 (6): 507–526. doi:10.1039/B002635M. PMID   11152419.
3. Voet, Donald; Voet, Judith G. (2011). Biochemistry (4. ed.). Hoboken, NJ: Wiley. ISBN   978-0-470-57095-1.
4. Enzyme 2.5.1.61 at KEGG Pathway Database.
5. 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.