MPO（髓过氧化物酶）是一种重要的溶酶体酶，主要在中性粒细胞和单核细胞的嗜天青颗粒中表达，属于血红素过氧化物酶基因家族。该基因位于人类17号染色体（17q22），编码的MPO蛋白在先天免疫防御中起关键作用，通过催化过氧化氢和氯离子反应生成次氯酸（一种强效杀菌剂），从而杀灭吞噬的病原体。MPO还参与炎症反应的调节，能氧化多种生物分子如脂蛋白，与动脉粥样硬化的发展相关。MPO基因突变可能导致遗传性MPO缺乏症，患者通常无症状但可能增加真菌感染风险，部分突变会完全丧失酶活性。MPO过表达与多种炎症性疾病相关，如类风湿性关节炎、阿尔茨海默病和心血管疾病，因其过度产生的活性氧物种会加剧组织氧化损伤。相反，MPO表达降低可能削弱先天免疫功能，但也被认为可能减少氧化应激相关的慢性病风险。MPO属于血红素过氧化物酶家族，该家族成员均含有保守的血红素辅基，具有氧化还原活性，参与宿主防御和免疫调节。MPO活性还影响其他基因表达，如通过NF-κB通路调控炎症因子（如TNF-α、IL-6）的产生。在临床诊断中，MPO是急性髓性白血病（AML）的标志物，其抗体还与ANCA相关血管炎（如肉芽肿性多血管炎）密切相关。

髓过氧化物酶（MPO）是构成中性粒细胞嗜苯胺蓝颗粒的主要成分骨髓分化过程中合成的血红素蛋白。产生作为单链前体，髓过氧化物酶随后被切割成一个轻链和重链。成熟的髓过氧化物酶是2轻链和2条重链组成的四聚体。这种酶产生次卤酸的中央到嗜中性粒细胞的杀菌活性。 [由RefSeq的，2014年11月提供]

Myeloperoxidase (MPO) is a critical lysosomal enzyme encoded by a gene located on human chromosome 17q22, belonging to the heme peroxidase gene family, which is characterized by the presence of a conserved heme cofactor that confers redox activity to its members. Primarily expressed in the azurophilic granules of neutrophils and monocytes, the MPO protein plays a pivotal role in innate immune defense by catalyzing the reaction between hydrogen peroxide and chloride ions to generate hypochlorous acid, a potent bactericidal agent that eliminates phagocytized pathogens. Beyond its direct antimicrobial function, MPO is deeply involved in the modulation of inflammatory responses; it can oxidize various biomolecules, including lipoproteins, thereby contributing to the pathogenesis of atherosclerosis, and it influences the expression of other genes by regulating the production of inflammatory cytokines such as TNF-α and IL-6 via the NF-κB signaling pathway. The clinical significance of MPO is multifaceted: genetic mutations can lead to hereditary MPO deficiency, a condition that is often asymptomatic but may predispose individuals to fungal infections, with some variants resulting in a complete loss of enzymatic activity. Conversely, overexpression of MPO is associated with exacerbated tissue oxidative damage in various inflammatory conditions, including rheumatoid arthritis, Alzheimer’s disease, and cardiovascular diseases, whereas reduced expression may compromise innate immunity but potentially lower the risk of oxidative stress-related chronic diseases. Furthermore, MPO serves as a key diagnostic marker in hematology and immunology; it is a characteristic antigen in acute myeloid leukemia (AML) and is closely linked to ANCA-associated vasculitides, such as granulomatosis with polyangiitis, where autoantibodies against MPO are a hallmark of the disease.

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