Elsevier Inc. Alas2 Alas1 Alad Hmbs Uros Urod Tspo Cpox Ppox Fech Slc25a38 heme b coenzyme A CO2 porphobilinogen uroporphyrinogen III coproporphyrinogen III 5-aminolevulinic acid Slc25a38 ---> glycine citric acid cycle pathway ---> succinyl-CoA Fe2+ Fe2+ ---> heme b Fech ---> H+ protoporphyrin IX ---> heme b H+ succinyl-CoA ---> coenzyme A glycine ---> CO2 citric acid cycle pathway Slc25a38 ---> 5-aminolevulinic acid succinyl-CoA ---> 5-aminolevulinic acid glycine ---> 5-aminolevulinic acid porphobilinogen ---> hydroxymethylbilane 5-aminolevulinic acid ---> porphobilinogen uroporphyrinogen III ---> coproporphyrinogen III hydroxymethylbilane ---> uroporphyrinogen III protoporphyrinogen ---> protoporphyrin IX coproporphyrinogen III ---> protoporphyrinogen succinyl-CoA glycine hydroxymethylbilane protoporphyrinogen protoporphyrin IX coproporphyrinogen III ---> protoporphyrinogen