Zinc Protoporphyrin

Zinc protoporphyrin (ZPP) is a compound found in red blood cells when heme production is inhibited by lead and/or by lack of iron. Instead of incorporating a ferrous ion, to form heme, protoporphyrin IX, the immediate precursor of heme, incorporates a zinc ion, forming ZPP. The reaction to insert a ferrous ion into protoporphyrin IX is catalyzed by the enzyme ferrochelatase.