Biochemical analysis of a recombinant glutathione transferase from the cestode Echinococcus granulosus.
Glutathione transferases (GSTs) are believed to be a major detoxification system in helminths. We describe the expression and functional analysis of EgGST, a cytosolic GST from Echinococcus granulosus, related to the Mu-class of mammalian enzymes. EgGST was produced as an enzymatically active dimeric protein (rEgGST), with highest specific activity towards the standard substrate 1-chloro-2,4-dinitrobenzene (CDNB; 2.5 micromol min(-1)mg(-1)), followed by ethacrynic acid. Interestingly, rEgGST displayed glutathione peroxidase activity (towards cumene hydroperoxide), and conjugated reactive carbonyls (trans-2-nonenal and trans,trans-2,4-decadienal), indicating that it may intercept damaging products of lipid peroxidation. In addition, classical GST inhibitors (cybacron blue, triphenylthin chloride and ellagic acid) and a number of anthelmintic drugs (mainly, hexachlorophene and rafoxanide) were found to interfere with glutathione-conjugation to CDNB; suggesting that they may bind to EgGST. Considered globally, the functional properties of rEgGST are similar to those of putative orthologs from Echinococcus multilcularis and Taenia solium, the other medically important cestodes. Interestingly, our results also indicate that differences exist between these closely related cestode GSTs, which probably reflect specific biological functions of the molecules in each parasitic organism.
Harispe
Laura
L
Sección Bioquímica, Facultad de Ciencias, UdelaR, Igua 4225, Montevideo, CP 11400, Uruguay.
García
Gabriela
G
Arbildi
Paula
P
Pascovich
Leticia
L
Chalar
Cora
C
Zaha
Arnaldo
A
Fernandez
Cecilia
C
Fernandez
Veronica
V
D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D001555:Benzene Derivatives / Q000378:metabolism; D019281:Dimerization; D004137:Dinitrochlorobenzene / Q000378:metabolism; D048209:Echinococcus granulosus / Q000201:enzymology* / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004976:Ethacrynic Acid / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
D000447:Aldehydes; D001555:Benzene Derivatives; D004137:Dinitrochlorobenzene; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; C057349:2,4-decadienal; C013166:2-nonenal; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D004976:Ethacrynic Acid; C007164:cumene hydroperoxide