Function
Myeloperoxidase (MPO) plays a major role in the oxygen-dependent microbicidal system of neutrophils. EPO from eosinophilic granulocytes participates in immunological reactions, and potentiates tumor necrosis factor (TNF) production and hydrogen peroxide release by human monocyte-derived macrophages. MPO (and possibly EPO) primarily use Cl-ions and H2O2 to form hypochlorous acid (HOCl), which can effectively kill bacteria or parasites. In secreted fluids, LPO catalyses the oxidation of thiocyanate ions (SCN-) by H2O2, producing the weak oxidizing agent hypothiocyanite (OSCN-), which has bacteriostatic activity.TPO uses I- ions and H2O2 to generate iodine, and plays a central role in the biosynthesis of thyroid hormones T3 and T4. Myeloperoxidase (PDB 1dnu), for example, resides in the human nucleus and lysosome and acts as a defense response to oxidative stress, preventing apoptosis of the cell.
Read more about this topic: Animal Heme-dependent Peroxidases
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