Question

Which enzyme catalyzes the insertion of iron into protoporphyrin IX during heme synthesis?

• A. Ferrochelatase
• B. ALA Synthase
• C. Porphobilinogen Deaminase
• D. Uroporphyrinogen Decarboxylase

Hint:

{Ferrochelatase} catalyzes the {final step of heme synthesis} by inserting Fe$^{2+}$ into protoporphyrin IX to form heme.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept: Heme synthesis involves a complex series of enzymatic reactions occurring in both the mitochondria and the cytoplasm of cells.
Step 2: Key Formula or Approach: The process requires tracing the final enzymatic step in the heme synthesis pathway where the iron molecule is physically incorporated into the porphyrin ring.
Step 3: Detailed Explanation: Ferrochelatase (also known as heme synthase) is the mitochondrial enzyme responsible for catalyzing the final step of heme synthesis, which is the insertion of ferrous iron (\(Fe^{2+}\)) into protoporphyrin IX to form heme.
ALA Synthase catalyzes the first and rate-limiting step of heme synthesis (forming \(\delta\)-aminolevulinic acid).
Porphobilinogen Deaminase and Uroporphyrinogen Decarboxylase are enzymes involved in the intermediate, cytoplasmic steps of the pathway.
Step 4: Final Answer: Ferrochelatase is the specific enzyme that catalyzes the insertion of iron into protoporphyrin IX.