glutathioneperoksidaasin

Glutathione peroxidase (GSH-Px) is a family of selenocysteine-containing antioxidant enzymes that play a critical role in cellular defense mechanisms. These enzymes catalyze the reduction of hydrogen peroxide (H₂O₂) and lipid hydroperoxides to their corresponding alcohols, thereby protecting cells from oxidative damage. The primary function of glutathione peroxidase is to detoxify reactive oxygen species (ROS), such as hydrogen peroxide and organic hydroperoxides, which can otherwise damage cellular components like DNA, proteins, and lipids.

Glutathione peroxidase requires glutathione (GSH) as a cofactor, which is oxidized in the process and later regenerated by glutathione reductase. The enzyme is classified into four main types: cytosolic (GPx1), gastrointestinal (GPx2), plasma (GPx3), and membrane-bound (GPx4). Each subtype has distinct tissue distributions and roles, contributing to overall antioxidant defense in different cellular compartments.

GPx1 is the most abundant form, found primarily in the cytosol of most tissues, where it helps neutralize hydrogen peroxide. GPx2 is localized to the gastrointestinal tract, where it protects against dietary lipid hydroperoxides. GPx3 circulates in the bloodstream, providing extracellular antioxidant protection, while GPx4 is associated with membranes and mitochondria, playing a key role in preventing lipid peroxidation and maintaining membrane integrity.

Deficiencies in glutathione peroxidase activity have been linked to increased susceptibility to oxidative stress-related diseases, including cardiovascular disorders, neurodegenerative conditions, and certain cancers. Genetic variations affecting GSH-Px expression or activity may also influence individual susceptibility to oxidative damage. Research continues to explore the therapeutic potential of modulating glutathione peroxidase levels to enhance antioxidant defenses and mitigate oxidative stress-related pathologies.