Myeloperoxidase (MPO) is a peroxidaseenzyme that in humans is encoded by the MPOgene on chromosome 17.[5] MPO is most abundantly expressed in neutrophils (a subtype of white blood cells), and produces hypohalous acids to carry out their antimicrobial activity, including hypochlorous acid, the sodium salt of which is the chemical in bleach.[5][6] It is a lysosomal protein stored in azurophilic granules of the neutrophil and released into the extracellular space during degranulation.[7] Neutrophil myeloperoxidase has a heme pigment, which causes its green color in secretions rich in neutrophils, such as mucus and sputum.[8] The green color contributed to its outdated name verdoperoxidase.
Myeloperoxidase is found in many different organisms including mammals, birds, fish, reptiles, and amphibians.[citation needed] Myeloperoxidase deficiency is a well-documented disease among humans resulting in impaired immune function.[9]
^Kinkade JM, Pember SO, Barnes KC, Shapira R, Spitznagel JK, Martin LE (Jul 1983). "Differential distribution of distinct forms of myeloperoxidase in different azurophilic granule subpopulations from human neutrophils". Biochemical and Biophysical Research Communications. 114 (1): 296–303. doi:10.1016/0006-291x(83)91627-3. PMID6192815.
^Le T, Bhushan V, Sochat M, Damisch K, Abrams J, Kallianos K, Boqambar H, Qiu, C, Coleman C (2021). First Aid for the USMLE Step 1 (2021 ed.). New York: McGraw Hill. p. 109. ISBN9781260467529.
^Cite error: The named reference pmid11111115 was invoked but never defined (see the help page).