Identification and characterization of glutathione S-transferase class Mu from the Rutilus frisii kutum

Glutathione S-transferases are one of the key enzymes in phase II of drug metabolism which play role in detoxification and oxidative stress metabolism in prokaryote and eukaryote cells, by binding reduced glutathione to the xenobiotics. Considering the importance of these enzymes in defying against pollution and in regard to the increasing amount of pollution in the Caspian Sea during recent years, a deeper knowledge about role and function of this enzyme as a key part of detoxification against the pollutants seems crucial. The goal of this study is identification and gene sequencing of glutathione S-transferase Mu in Rutilus frisii kutum. After RNA extraction from male fishes’ liver tissue, cDNA synthesis was the next step followed by PCR. Then the desired gene was inserted into vector pTZ57R/T followed by chemical transformation into E. coli DH5α competent cells. After plasmid extraction and gene sequencing, the partial GSTM sequence with 625 nucleotides was obtained. The nucleotide BLAST result shows more than 89% of identity with GSTM in other members of Cyprinidae that N-terminal region has a greater portion of this identity compared with C-terminal. The most abundant residue found in the GSTM sequence was lysine which has an important role in glutathione S-transferase structures. The GSTM nucleotide sequence was registered at the NCBI database with accession number KY211992.