Does the liver break down hydrogen peroxide?

The liver plays a crucial role in the metabolism and detoxification of various substances in the body, including hydrogen peroxide (H2O2). H2O2 is a reactive oxygen species (ROS) commonly produced as a byproduct of cellular processes.

In the liver, the breakdown of hydrogen peroxide primarily occurs through the action of enzymatic antioxidant systems:

Glutathione Peroxidase (GPx): GPx is a family of enzymes present in the liver that play a vital role in detoxifying H2O2. GPx catalyzes the reduction of H2O2 to water (H2O) using reduced glutathione (GSH) as an electron donor. GSH is an important antioxidant tripeptide.

Catalase: Catalase is another essential antioxidant enzyme. It directly decomposes H2O2 into water and oxygen (O2), without requiring any additional electron donors like GSH. Catalase is found in high concentrations in the liver and is responsible for a significant portion of the breakdown of H2O2.

Apart from these primary enzymatic mechanisms, other mechanisms may also contribute to hydrogen peroxide breakdown in the liver:

Ascorbic Acid (Vitamin C): Vitamin C can react with H2O2, especially in the presence of transition metal ions such as iron or copper. It helps neutralize H2O2 and reduce its harmful effects.

Peroxiredoxins: Peroxiredoxins are antioxidant enzymes found in the liver that contribute to H2O2 metabolism. They reduce H2O2 using GSH as an electron donor.

Overall, the liver is well-equipped with various enzymatic and non-enzymatic systems to break down hydrogen peroxide and protect its cells from oxidative damage caused by excess ROS.