Kinetic studies on the glutathione peroxidase activity of selenium-containing glutathione transferase.
Selenium-containing glutathione transferase (seleno-GST) was generated by biologically incorporating selenocysteine into the active site of glutathione transferase (GST) from a blowfly Lucilia cuprina (Diptera: Calliphoridae). Seleno-GST mimicked the antioxidant enzyme glutathione peroxidase (GPx) and catalyzed the reduction of structurally different hydroperoxides by glutathione. Kinetic investigations reveal a ping-pong kinetic mechanism in analogy with that of the natural GPx cycle as opposed to the sequential one of the wild type GST. This difference of the mechanisms might result from the intrinsic chemical properties of the incorporated residue selenocysteine, and the selenium-dependent mechanism is suggested to contribute to enhancement of the enzymatic efficiency.
Yu
Huijun
H
Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, Jilin University, Changchun 130012, People's Republic of China.
Liu
Junqiu
J
Liu
Xiaoman
X
Zang
Tianzhu
T
Luo
Guimin
G
Shen
Jiacong
J
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001665:Binding Sites; D002384:Catalysis; D004175:Diptera / Q000201:enzymology*; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D007700:Kinetics; D012643:Selenium / Q000378:metabolism; D017279:Selenocysteine / Q000378:metabolism*
D000975:Antioxidants; D017279:Selenocysteine; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D005978:Glutathione; D012643:Selenium