 Initially, the carboxylate group on γ-glutamylcysteine is converted into an acyl phosphate by the transfer of an inorganic phosphate group of ATP to generate an acyl phosphate intermediate.Then the amino group of glycine participates in a nucleophilic attack, displacing the phosphate group and forming GSH.After the final GSH product is made, it can be used by glutathione peroxidase to neutralize reactive oxygen species (ROS) such as H2O2 or Glutathione S-transferases in the detoxification of xenobiotics.