In hereditary protoporphyria, which enzyme of heme synthesis is decreased?

  1. Coproporphyrinogen oxidase
  2. Ferrochelatase
  3. Porphobilinogen synthase
  4. Uroporphyrinogen oxidase
  5. Uroporphyrinogen synthase


This point was not covered explicitly in the instructional material.
You can make an educated guess from the name of the condition, "protoporphyria."
It sounds like there is an accumulation of a protoporphyrin,
and we know that a protoporphyrin (protoporphyrin IX) is produced during heme synthesis.
It would accumulate if there were a defect in the next step, which is catalyzed by ferrochelatase.

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