MYELOPEROXIDASE (MPO; EC 1.11.2.2) is a peroxidase enzyme and can be found in neutrophil, monocytes, and some soft tissue macrophages. MPO has an ability to use chloride as a cosubstrate with hydrogen peroxide to generate hypochlorous acid, a powerful antimicrobial agent produced by neutrophils. However, an excessive production of hypochlorous acid can lead to oxidative stress and tissues damage. Inflammation may also result when MPO oxidizes various substances such as phenols and anilines. Studies show that increased MPO levels may increase the risk of myocardial infarction and cardiovascular disease. This EnzyFluoTM myeloperoxidase (MPO) assay kit is based on the MPO enzyme reaction with hydrogen peroxide (H2O2) which oxidizes the dye reagent to a highly fluorescent product. The fluorescence intensity of this product, measured at &labda;ex/em = 530/585 nm, is proportional to the total peroxidation activity in the sample. The provided MPO inhibitor is used to suppress peroxidase activity due to MPO in order to differentiate other peroxidase activities that may be present in the samples.