Glutathione Peroxidase activity testing is no longer performed by Diagnostiki Athinon. For the assessment of redox balance and the glutathione system, please see Glutathione
Glutathione peroxidase (GPx) is a family of enzymes with peroxidase activity. Its primary functional mission is to protect the body from oxidative stress.
Glutathione peroxidase is an essential enzyme that removes peroxides from living cells. Glutathione peroxidase plays a vital role in protecting cells from damage caused by free oxygen species formed during peroxide breakdown. Cell lipids are susceptible to reactions with active free radicals, leading to lipid peroxidation. GPx reduces peroxides to alcohols, preventing the formation of active free radicals, and glutathione serves as a reducing agent. Many glutathione isoenzymes, encoded by different genes, are found in various cell compartments and use different substrates. So far, researchers have identified eight different isoenzymes (GPx1-8) in humans.
Glutathione peroxidase catalyzes the reduction of hydrogen peroxide and many other organic peroxides to water and the corresponding stable alcohols using cellular glutathione as a reducing agent. Most cellular glutathione peroxidases are tetrameric enzymes consisting of four identical monomers, each with a molecular weight of 22 kDa and a selenocysteine at its active site. Selenocysteine directly donates electrons to the peroxide and is oxidized during the process. The enzyme then uses reduced glutathione as a hydrogen donor to regenerate selenocysteine. Some of the GPx isoenzymes do not contain selenium at their active site.
Cellular glutathione peroxidase is found in all tissues. However, various diseases can affect its levels. Low serum glutathione peroxidase levels have been shown to contribute to the appearance and progression of vitiligo. Lower enzyme levels were also observed in patients with proteinuria and type 2 diabetes. Glutathione peroxidase activity was much lower in patients with recurrent multiple sclerosis. Glutathione peroxidase has also been shown to play a role in the development of celiac disease.
Measuring glutathione peroxidase in oxidative stress tests can help identify the underlying causes of many chronic diseases and clinical disorders and design appropriate, individualized treatment interventions.
