D-aminolaevulinic acid

Barlow, J. J., Baruah, J. K. and Davison, A. N. (1977). D-Aminolaevulinic acid dehydratase activity and focal brain haemorrhages in lead-treated rats. Acta Neuropathol. (Berlin), 39, 219... 

Synthesis of haem is readily accomplished from simple precursors. In the first step of porphyrin synthesis succinyl-CoA, which is produced in the citrate cycle and during the metabolism of various amino acids, is condensed with glycine to give d-aminolaevulinic acid, and it is this reaction which is rate-controlling. Subsequently two molecules of d-aminolaevulinic acid condense to form porphobilinogen and four molecules of porphobilinogen undergo a series of reactions to produce protoporphyrin which combines with ferrous ions to form haem. 

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