[7][8] CPOX, the sixth enzyme of the haem biosynthetic pathway, converts coproporphyrinogen III to protoporphyrinogen IX through two sequential steps of oxidative decarboxylation.

[10] CPOX is an enzyme involved in the sixth step of porphyrin metabolism it catalyses the oxidative decarboxylation of coproporphyrinogen III to proto-porphyrinogen IX in the haem and chlorophyll biosynthetic pathways.

[13] After proteolytic processing, the protein is present as a mature form of a homodimer with a molecular mass of 37 kDa.

[14] Hereditary coproporphyria (HCP) and harderoporphyria are two phenotypically separate disorders that concern partial deficiency of CPOX.

[17] CPOX has been shown to interact with the atypical keto-isocoproporphyrin (KICP) in human subjects with mercury (Hg) exposure.