Protective role of the freshwater rotifer Brachionus calyciflorus glutathione S-transferase zeta 3 recombinant protein in response to Hg and Cd.

Gluatathione S-transferases (GSTs) play a major role in phase II detoxification pathway to defend organisms in response to oxidative stress induced by xenobiotics and toxicants. To reveal the role of the recombinant GST zeta protein from the freshwater rotifer Brachionus calyciflorus, we isolated the zeta class GST in the freshwater rotifer B. calyciflorus. The recombinant B. calyciflorus GST zeta protein was highly expressed in the transformed Escherichia coli using pET28a vector. To determine its characteristics, effects of pH and temperature on B. calyciflorus GST zeta with enzymatic kinetics were also studied. In addition, a disk diffusion assay, uncovering the ability of transformed GST zeta in Escherichia coli, revealed that E. coli-transformed GST zeta significantly protected the transformed E. coli cells in response to oxidative stress induced by HO and metals such as mercury and cadmium. These results suggest that B. calyciflorus GST zeta recombinant protein is likely playing an important role to defend in response to metal-induced oxidative stress, providing a better understanding on the possible antioxidant role of GST zeta class in B. calyciflorus.