Malate-quinone oxidoreductase (parasite mitochondria) (MQO)

Malate-quinone oxidoreductase (MQO) is a membrane-bound mitochondrial enzyme found in a range of parasitic organisms, notably Plasmodium species (malaria parasites), some helminths (e.g., Echinococcus multilocularis), and certain bacteria. It catalyzes the oxidation of malate to oxaloacetate while concurrently reducing mitochondrial quinone (often rhodoquinone or ubiquinone, depending on the organism) to quinol, effectively linking the tricarboxylic acid cycle to the electron transport chain. MQO is functionally essential in parasites such as Plasmodium, which lack the typical mitochondrial malate dehydrogenase, making them reliant on MQO for TCA cycle completion and mitochondrial respiration. MQO is structurally distinct from human enzymes, making it an attractive target for antiparasitic drug discovery. Inhibitors that selectively block MQO have been shown to kill parasites in vitro by collapsing mitochondrial energy production. The enzyme's central role in parasite metabolism and absence from host mitochondria underlies its identification as a promising biochemical and pharmacological target.

Other names

mitochondrial malate-quinone oxidoreductasePfMQO (for Plasmodium falciparum)parasite mitochondrial quinone reductasemalaria parasite MQO

Inhibition of MQO disrupts the TCA cycle and mitochondrial electron transport, leading to parasite death via ATP depletion and impaired metabolism. The inhibitors often compete with substrate malate or quinone-binding, blocking electron flow into the mitochondrial respiratory chain.