Biochemistry · Heme Synthesis and Porphyrias

Which enzyme catalyses the final step of heme biosynthesis, inserting ferrous iron into protoporphyrin IX?

A Coproporphyrinogen oxidase
B Protoporphyrinogen oxidase
C Ferrochelatase ✓
D Heme oxygenase

Correct answer: C. Ferrochelatase

Explanation

Ferrochelatase catalyses the insertion of Fe2+ into protoporphyrin IX, forming heme. This is the eighth and final step and occurs on the inner mitochondrial membrane. Protoporphyrinogen oxidase is the seventh step. Heme oxygenase initiates heme degradation, not synthesis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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