Protoporphyrinogen Oxidase (PPOX)

PPOX is a human gene that produces an enzyme called protoporphyrinogen oxidase. This enzyme is responsible for the seventh step in heme production. Heme is the portion of hemoglobin that carries oxygen in the blood from the lungs to the rest of the body. Each of the steps in heme production is controlled by a separate gene. Protoporphyrinogen oxidase removes hydrogen atoms from protoporphyrinogen IX (the product of the sixth step in the production of heme) to form protoporphyrin IX. One additional enzyme must modify protoporphyrin IX before it becomes heme.This gene encodes the penultimate enzyme of heme biosynthesis, which catalyzes the 6-electron oxidation of protoporphyrinogen IX to form protoporphyrin IX. This protein is a flavoprotein associated with the outer surface of the inner mitochondrial membrane.