Plasmodium falciparum heme polymerase

Plasmodium falciparum heme polymerase is a putative enzymatic or enzymatic-like function in the malaria parasite Plasmodium falciparum, responsible for converting toxic free heme (released during hemoglobin digestion in the parasite's acidic digestive vacuole) into inert crystalline hemozoin. This detoxification is crucial for parasite survival inside human red blood cells. While commonly referred to as "heme polymerase," the molecular identity of this enzyme remains uncertain and is sometimes attributed to proteins such as histidine-rich protein II (HRP II), which can promote heme polymerization into hemozoin in vitro[5][6]. Chloroquine, quinine, and related drugs act by inhibiting this process, causing the accumulation of toxic heme and parasite death[6][2]. Drug resistance to inhibitors of this pathway is a major clinical concern. Current evidence suggests the process is a critical target for antimalarial drug development, but the exact structural nature ("canonical" enzyme vs. protein-mediated crystal templating) and nomenclature of the "heme polymerase" remains under debate.[5][6] Important note: "Plasmodium falciparum heme polymerase" is often used as a functional rather than a strictly defined biochemical entity; recent research suggests the hemozoin formation process may not be catalyzed by a classical enzyme, but instead mediated by proteins like HRP II, lipids, or non-enzymatic factors, so the target designation as a unique, well-defined enzyme is potentially inaccurate or ambiguous[5][2][6]. For maximal clarity in structured data, HRP II or "hemozoin formation pathway" may be preferable canonical forms.

Other names

heme polymerasehemozoin synthasehistidine-rich protein II (HRP II)Plasmodium heme detoxification pathway

Drug binding inhibits heme polymerization, leading to toxic accumulation of heme and death of the parasite[2][6]