Myeloperoxidase

Myeloperoxidase (MPO) is a enzyme that in humans is encoded by the MPO gene on chromosome 17. It is most abundantly expressed in neutrophil granulocytes, a type of white blood cell. It is a lysosomal protein stored in azurophilic granules of the neutrophil and released into the extracellular space during inflammation.

Function

Myeloperoxidase has a heme-containing peroxidase secreted by neutrophils and monocytes during inflammation. It is involved in the immune defense against microorganisms. MPO catalyzes the production of hypochlorous acid (HOCl) from hydrogen peroxide (H2O2) and chloride anion (Cl-) or the equivalent from a non-chloride source.

Clinical significance

MPO has been implicated in numerous diseases including atherosclerosis, lung cancer, Alzheimer's disease and Parkinson's disease. It is associated with vasculitis, various forms of glomerulonephritis, and cryoglobulinemia.

See also

• Peroxidase
• Neutrophil granulocytes
• Inflammation

External links

• MPO gene on NCBI
• MPO protein on UniProt