Glutathione S-transferase in helminth parasites.

Glutathione S-transferases (GSTs; EC 2.5.1.18) are a large family of multifunctional dimeric enzymes that conjugate reduced glutathione to electrophilic centers in hydrophobic organic compounds. The GST enzymatic activity has been described in the adult and larval stages of helminths. Several forms and isoforms of the enzyme have been purified and GST genes have also been isolated and expressed as recombinant proteins. The helminth GSTs participate in detoxification of lipid hydroperoxides and carbonyl cytotoxics produced by oxygen-reactive intermediates (ORI). The ORIs can come from the endogenous parasite metabolism or from the host immune system. The helminth GSTs are able to conjugate glutathione to xenobiotic compounds or to bind to anthelminth drugs. GST is usually localized near to host-parasite interface. This enzyme has been identified as a potentially vulnerable target in immunotherapy and chemotherapy. The present review compiles current knowledge about the biochemical characteristics of the enzyme, its presence, localization, induction, structural heterogeneity, relationship with mammalian GSTs, detoxification capacity and ability to induce protection in several animal models.