Topic summary
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.
Porphobilinogen can be described as a pyrrole with substituents at positions 2, 3 and 4. These substituents are respectively, an aminomethyl group −CH2−NH2, a carboxymethyl group−CH2−COOH, and a carboxyethyl group −CH2−CH2−COOH.