myeloperoksidaasiin

Myeloperoksidaasiin, often abbreviated as MPO, is an enzyme primarily found in neutrophils and monocytes, which are types of white blood cells. It plays a crucial role in the innate immune system's defense against microbial infections. MPO is located in the azurophilic granules of these cells. When neutrophils and monocytes are activated, for example, in response to an inflammatory signal or the presence of pathogens, MPO is released into the phagosome or extracellular space.

Within the phagosome, MPO catalyzes the conversion of hydrogen peroxide and chloride ions into hypochlorous acid (HOCl). Hypochlorous acid is a potent oxidant that can effectively kill bacteria, fungi, and viruses. This oxidative burst is a key mechanism by which phagocytic cells eliminate invading microorganisms. MPO also contributes to the inflammatory response, and its products can influence tissue remodeling and the recruitment of other immune cells.

Elevated levels of MPO in plasma are considered a marker for inflammation and oxidative stress. It has been studied in the context of various diseases, including cardiovascular disease, where MPO activity is associated with the oxidation of low-density lipoprotein (LDL) cholesterol, a process implicated in atherosclerosis. Research continues to explore the multifaceted roles of MPO in both health and disease.