Plasmodium heme detoxification pathway

The Plasmodium heme detoxification pathway operates in the parasite’s acidic digestive vacuole during intraerythrocytic stages, where hemoglobin digestion releases toxic free heme that is detoxified primarily by crystallization into inert hemozoin (also known as β-hematin). Hemozoin formation is essential for parasite survival and is a validated antimalarial target; multiple drug classes, including quinoline antimalarials and endoperoxides, act by inhibiting heme-to-hemozoin crystallization or by forming toxic complexes/adducts with heme, thereby increasing exchangeable heme and killing the parasite. Mechanistic models include direct interference with crystal nucleation and growth via surface adsorption, heme binding/complexation, and heme alkylation by activated endoperoxides in the digestive vacuole; heme detoxification protein (HDP) and associations with hemoglobinases (e.g., falcipain-2) have been implicated in facilitating hemozoin biocrystallization and coupling to hemoglobin degradation.

Other names

heme-to-hemozoin crystallization pathwayhemozoin formation pathwayβ-hematin formationheme detoxification via hemozoinPlasmodium hemozoin biocrystallization pathway

inhibition of heme-to-hemozoin crystallization; binding/complexation with free heme (ferriprotoporphyrin IX) leading to toxic drug–heme adducts; surface adsorption to growing hemozoin crystal faces disrupting crystal growth; alkylation of heme within the digestive vacuole following endoperoxide activation (artemisinin/ozonides)