Chemistry:Porphobilinogen
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 –CH
2–NH
2, an acetic acid (carboxymethyl) group –CH
2–COOH, and a propionic acid (carboxyethyl) group –CH
2–CH
2–COOH.
Biosynthesis
In a early step of the porphyrin biosynthesis pathway, porphobilinogen is generated from aminolevulinic acid (ALA) by the enzyme ALA dehydratase.[2]
- REDIRECT Template:Chemical reaction
Metabolism
Next in the pathway towards porphyrins, four molecules of porphobilinogen are combined into hydroxymethyl bilane by the enzyme porphobilinogen deaminase:[2][3][4]
- REDIRECT Template:Chemical reaction
Pathologies
Acute intermittent porphyria causes an increase in urinary porphobilinogen.[5]
References
- ↑ Paul R. Ortiz de Montellano (2008). Wiley Encyclopedia of Chemical Biology. John Wiley & Sons. doi:10.1002/9780470048672.wecb221. ISBN 978-0470048672.
- ↑ 2.0 2.1 Battersby, Alan R. (2000). "Tetrapyrroles: The pigments of life". Natural Product Reports 17 (6): 507–526. doi:10.1039/B002635M. PMID 11152419.
- ↑ Voet, Donald; Voet, Judith G. (2011). Biochemistry (4. ed.). Hoboken, NJ: Wiley. ISBN 978-0-470-57095-1.
- ↑ Enzyme 2.5.1.61 at KEGG Pathway Database.
- ↑ 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.
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