The characterization of cytosolic glutathione transferase from four species of seaturtles: Loggerhead (Caretta caretta), green (Chelonia mydas), olive ridley(Lepidochelys olivacea), and hawksbill (Eretmochelys imbricata

摘要

Glutathione s-transferases (GST) play a critical role in the detoxification of exogenous and endogenouselectrophiles, as well as the products of oxidative stress. As compared to mammals, GST activity has not beenextensively characterized in reptiles. Throughout the globe, most sea turtle populations face the risk ofextinction. Of the natural and anthropogenic threats to sea turtles, the effects of environmental chemicalsand related biochemical mechanisms, such as GST catalyzed detoxification, are probably the least understood.In the present study, GST activity was characterized in four species of sea turtles with varied life histories andfeeding strategies: loggerhead (Caretta caretta), green (Chelonia mydas), olive ridley (Lepidochelys olivacea),and hawksbill (Eretmochelys imbricata). Although similar GST kinetics was observed between species, rates ofcatalytic activities using class-specific substrates show inter- and intra-species variation. GST from thespongivorous hawksbill sea turtle shows 3-4.5 fold higher activity with the substrate 4-nitrobenzylchloridethan the other 3 species. GST from the herbivorous green sea turtle shows 3 fold higher activity with thesubstrate ethacrynic acid than the carnivorous olive ridley sea turtle. The results of this study may provideinsight into differences in biotransformation potential in the four species of sea turtles and the possiblehealth impacts of contaminant biotransformation by sea turtles.