Oxidized glutathione

Oxidized glutathione (also known as GSSG) is a crucial compound in biology that plays a significant role in antioxidant defense, nutrient metabolism, and regulation of cellular events. It is the oxidized form of glutathione, a tripeptide composed of glutamate, cysteine, and glycine.

Structure and Synthesis

Oxidized glutathione is a dimeric disulfide formed from two glutathione molecules. In the body, it is synthesized from glutamate, cysteine, and glycine in two ATP-dependent steps. The first step is catalyzed by glutamate-cysteine ligase, and the second step is catalyzed by glutathione synthetase.

Function

The primary function of oxidized glutathione is to protect the organism from oxidative stress. It does this by serving as a substrate for the enzyme glutathione peroxidase, which reduces hydrogen peroxide and lipid peroxides to water and the corresponding alcohols, respectively. This process converts oxidized glutathione back to its reduced form, glutathione.

In addition to its role in antioxidant defense, oxidized glutathione also plays a role in the regulation of cellular proliferation, apoptosis, immune response, and detoxification. It is also involved in the post-translational modification of proteins through a process known as S-glutathionylation.

Clinical Significance

Alterations in the levels of oxidized glutathione have been associated with a number of diseases, including cancer, neurodegenerative diseases, cardiovascular diseases, and aging. As such, it is considered a potential therapeutic target for these conditions.

See Also

• Glutathione
• Glutathione peroxidase
• Glutathione synthetase
• Glutamate-cysteine ligase
• S-glutathionylation