Factors Influencing Glutathione S-transferases in Daphnia magna

Abstract

Glutathione S-transferases (GSTs) are an important family of xenobiotic biotransforming enzymes that can make toxicity tests variable. Daphnia magna is commonly used in ecotoxicology testing because they are easy to culture, have a short life cycle, and reproduce by parthenogenesis. The specific activities of glutathione S-transferases were determined in D. magna of different ages and D. magna with eggs and without eggs in their brood chambers and in both cases there was a significant difference in the specific activity between the groups. D. magna were exposed to clofibrate and it was determined that clofibrate does not significantly alter the specific activities of GSTs in D. magna. Glutathione S-transferases were purified from D. magna using affinity chromatography and then the purified sample was run on a SDS-PAGE gel to determine the molecular weight of the subunits of glutathione S-transferases which fell in the range that was consistent with previous studies.