early mitochondrial: Aminolevulinic acid synthase (ALAS1, ALAS2) · Porphobilinogen synthase
cytosolic: Porphobilinogen deaminase · Uroporphyrinogen III synthase · Uroporphyrinogen III decarboxylase · Coproporphyrinogen III oxidase
spleen: Heme oxygenase · Biliverdin reductase