The recovery of MPO spiked to levels throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=4)
Platelet-poor EDTA Plasma (n=4)
Platelet-poor Heparin Plasma (n=4)
To assess the linearity of the assay, samples containing and/or spiked with high concentrations of MPO were serially diluted with the appropriate Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Preparation and Storage
Store the unopened product at 2 - 8 °C. Do not use past expiration date.
Myeloperoxidase (MPO) is a heme-containing enzyme belonging to the XPO subfamily of peroxidases. It is an abundant neutrophil and monocyte glycoprotein that catalyzes the hydrogen peroxide dependent formation of hypochlorus acid (HOCl) and other reactive species. Enzymatically active MPO is a disulfide-linked tetramer that contains two heme groups and two copies each of the heavy and light chains. MPO binds Albumin, MMR, Cytokeratin 1 on vascular endothelial cells, HMW Kininogen, and Integrin CD11b/CD18 on neutrophils. These interactions promote MPO clearance, a reduction of nitric oxide and bradykinin levels, reduced vasodilation, and continued neutrophil activation. Neutrophil MPO is stored in cytoplasmic azurophilic granules. Upon cellular activation and degranulation, MPO is delivered into phagosomes where it is required for the killing of phagocytosed bacteria. Activated neutrophils also release granule contents extracellularly. Elevated plasma MPO levels have been associated with a variety of clinical conditions including systemic inflammation, eclampsia, risk of cardiovascular events, vascular endothelial dysfunction, severity of multiple sclerosis, and prospective mortality and oxidative stress during hemodialysis.
Refer to the product for complete assay procedure.
Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.
Prepare all reagents, standard dilutions, and samples as directed in the product insert.
Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.
Add Assay Diluent
For Serum, Plasma, & Human Milk Samples: Add 50 µL of Assay Diluent to each well. For Cell Culture Supernate, Cell Lysate, Saliva, & Urine Samples: Add 100 µL Assay Diluent to each well.
50 µL Standard, Control, or Sample
Add 50 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours on a horizontal orbital microplate shaker.
Aspirate each well and wash, repeating the process 3 times for a total of 4 washes.
200 µL Conjugate
Add 200 µL of Conjugate to each well.
For Serum, Plasma, & Human Milk Samples: Cover with a new plate sealer, and incubate at room temperature for 2 hours on the shaker. For Cell Culture Supernate, Cell Lysate, Saliva, & Urine Samples: Cover with a new plate sealer, and incubate at room temperature for 1 hour on the shaker.
Aspirate and wash 4 times.
200 µL Substrate Solution
Add 200 µL Substrate Solution to each well. Incubate at room temperature for 20 minutes on the benchtop. PROTECT FROM LIGHT.
50 µL Stop Solution
Add 50 µL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.
R&D Systems personnel manually curate a database that contains references using R&D Systems products.
The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.