Heme detoxification pathway (HDP) (HDP)

The heme detoxification pathway is a critical survival mechanism employed by Plasmodium species, the causative agents of malaria, during their intraerythrocytic stage (PubMed: 18704164). As the parasite consumes host hemoglobin, it releases large quantities of free heme (ferriprotoporphyrin IX), which is highly toxic due to its ability to generate reactive oxygen species and disrupt cellular membranes (PubMed: 16122231). To mitigate this toxicity, the parasite converts free heme into an insoluble, chemically inert crystalline form known as hemozoin or malaria pigment (PubMed: 8662506). This process is primarily mediated by the Heme Detoxification Protein (HDP) and occurs within the parasite's acidic food vacuole (UniProt: Q8I2V9). Many classic antimalarial drugs, such as chloroquine and quinine, exert their therapeutic effect by binding to heme monomers or the growing crystal face, thereby preventing further polymerization (PubChem: CID 2719). The resulting accumulation of free heme leads to oxidative stress and eventual death of the parasite, making this pathway one of the most successful targets in the history of antimalarial chemotherapy (StatPearls: NBK537053).

Other names

Hemozoin formationHeme biocrystallizationHeme polymerizationFerriprotoporphyrin IX detoxification

Inhibition of heme polymerization into hemozoin, resulting in the accumulation of toxic free ferriprotoporphyrin IX which causes oxidative damage and parasite lysis.