Hemoglobin digestion

Mechanism of Action. Although the drug s exact mechanism of action is unknown, mefloquine may exert antimalarial effects similar to chloroquine that is, these drugs inhibit hemoglobin digestion in malarial parasites, thus causing heme by-products to accumulate within the protozoa and cause toxicity and death of this parasite.65... 

Mechanism of Action. The exact mechanism of quinine is not known. This drug probably exerts antimalarial effects similar to those of chloroquine—that is, inhibition of hemoglobin digestion and subsequent accumulation of toxic heme by-products that lead to death in susceptible protozoa.22... 

The mechanism of action for such peroxidic compounds involves a reductive activation by iron in haem, released as a result of hemoglobin digestion by Plasmodium. This irreversible redox reaction affords carbon-centered free radicals causing the alkylation of haem and of proteins. One such protein (the sarcoplasmic-endoplasmic reticulum ATPase PfATP6) appears to be critical for parasite survival, and there is no indication for resistance by the parasite. However, treatment is expensive and recrudescence of malaria occurs often. Moreover, it was found that at high doses such compounds are neurotoxic. 

Merten and Ratzer (M32), using the hemoglobin digestion technique. 

Fig, 23. Quantitation of pepsin by paper electrophoresis and hemoglobin digestion in 165 lyophilized gastric juices of humans. From Class (C3). 

In 1937, Balls et al. [4] purified one of the proteolytic fractions and called their crystalline enzyme papain. This was an unfortunate choice, since the name papain is also used for the crude papaya latex containing multiple enzymes. In 1939, Lineweaver and Balls published a refinement of the isolation method, and they also reported the presence in the papaya latex of another proteinase with a higher ratio of milk-clotting to hemoglobin-digesting activity than papain [5], In 1941 Jansen and Balls presented a description of a second proteolytic enzyme [6]... 

Lew, V. L., Macdonald, L., Ginsburg, H., Krugliak, M., and Tiffert, T. (2004). Excess hemoglobin digestion by malaria parasites A strategy to prevent premature host cell lysis. Blood Cells Mol. Dis. 32,353-359. 

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