A putative glutathione peroxidase gene (Swiss-Prot accession number Z 68200) of Plasmodium falciparum, the causative agent of tropical malaria, was expressed in Escherichia coli and purified to electrophoretic homogeneity. Like phospholipid hydroperoxide glutathione peroxidase of mammals, it proved to be monomeric. It was active with H 2 O 2 and organic hydroperoxides but, unlike phospholipid hydroperoxide glutathione peroxidase, not with phosphatidylcholine hydroperoxide. With glutathione peroxidases it shares the ping-pong mechanism with infinite V max and K m when analyzed with GSH as substrate. As a homologue with selenocysteine replaced by cysteine, its reactions with hydroperoxides and GSH are 3 orders of magnitude slower than those of the selenoperoxidases. Unexpectedly, the plasmodial enzyme proved to react faster with thioredoxins than with GSH and most efficiently with thioredoxin of P. falciparum

No abstract

No abstract

No abstract

No abstract