Succinyl CoA Glycine

δ- Aminolevulinate

2 δ- Aminolevulinate

Porphobilinogen

4-Porphobilinogen

Uroporphyrinogen III

Coproporphyrinogen III

Protoporphyrinogen III

Protoporphyrin IX

Heme

δ- AminolevulinateSynthase

δ- Aminolevulinatedehydratase

Uroporphyrinogen I Synthase &

uroporphyrinogenIII cosynthase

Uroporphyrinogendecarboxylase

Coprophyrinogenoxidase

Protophyrinogenoxidase

FerrochelataseFe2+

4H+

4CO2

4CO2

4NH3

4H2O

CoASH

Synthesis of heme