Coproporphyrinogen III oxidase (CPOX)

Coproporphyrinogen III oxidase (CPOX) is a critical mitochondrial enzyme that catalyzes the sixth step of the heme biosynthetic pathway. It mediates the oxidative decarboxylation of coproporphyrinogen III into protoporphyrinogen IX, a necessary precursor for the final stages of heme production. Mutations in the CPOX gene lead to Hereditary Coproporphyria (HCP) and its variant Harderoporphyria, conditions characterized by the toxic accumulation of porphyrins and their precursors. This accumulation often results in acute neurovisceral attacks, characterized by severe abdominal pain and neurological dysfunction, as well as skin photosensitivity. In clinical practice, therapeutic interventions such as hemin (Panhematin) are used to provide feedback inhibition of the pathway, thereby reducing the production of these toxic intermediates. Recent research also identifies CPOX as a potential target for novel antibacterial therapies and as a biomarker in certain cancers like glioblastoma, where its expression levels correlate with diagnostic fluorescence.

Other names

Coproheme oxidaseCPOCPXCoproporphyrinogen-III oxidaseCoproporphyrinogenaseHereditary coproporphyria (HCP) protein

Catalyzes the two-step oxidative decarboxylation of the propionate side chains on rings A and B of coproporphyrinogen III to produce protoporphyrinogen IX.