Protoporphyrinogen oxidase

Protoporphyrinogen oxidase is an enzyme that 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.)

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.