GLUTATHIONE, GLUTATHIONE-RELATED ENZYMES, AND CATALASE ACTIVITIES IN THE EARTHWORM EISENIA-FETIDA-ANDREI

The aim of this work was to provide basic data on the antioxidant defe nces in the annelid Eisenia fetida andrei (E. f. a.). Methods for meas urement of three antioxidant enzymes-catalase (CAT), glutathione perox idase (GPX), and glutathione reductase (GR)-and of glutathione-S-trans ferase (GST) were optimized. GPX activity differed according to the su bstrate used: cumene hydroperoxide (CUOOH) or hydrogen peroxide (H2O2) . The effects on the enzyme activities of storage up to 2 months at -8 0 degrees C, -20 degrees C, and +4 degrees C were evaluated. The subce llular distribution (in cytosol, mitochondrial, and microsomal fractio ns) was examined. The properties and subcellular distribution of the e nzymes and glutathione were also characterized in dissected tissues an d body fluids. The GR activity decreased at -80 degrees C and was the only one not stable at this temperature. The four enzymes were localiz ed mainly in the cytosolic fraction. CAT distribution was unusual as i t was not associated with peroxisomes, its properties being consistent with a catalase-peroxidase, rather than a true catalase. However, thi s result could also be an artifact linked to the use of an inappropria te method to obtain the fractions. Our observations indicate the prese nce of a distinct cytosolic selenium-dependent GPX (Se-GPX), and of a possible microsomal Se-GPX. A strong non-Se-GPX activity was measured in the CF and CL, which could be linked to the peroxidase activity of fetidins secreted by coelomocytes and with the ROS production of these cells. This study seems to indicate that E. f. a. is well equipped fo r the metabolism of electrophilic and pro-oxidants through glutathione .