The MPO gene encodes myeloperoxidase, a lysosomal heme protein located in the azurophilic granules of polymorphonuclear (PMN) leukocytes and monocytes. In response to stimulation, MPO is activated to a transient intermediate with potent antimicrobial oxidizing capacity (PMID: 17650507). The mRNA is translated into a single 90 kDa protein that exhibits enzymatic activity and undergoes proteolytic maturation into a 59 kDa heavy chain and a 13.5 kDa light chain; these subunits then dimerize to form the mature tetramer, with mature MPO being an heterotetramer composed of two identical heavy chains and two identical light chains (PMID: 12773517). The 24 kDa material has a profile identical to that of the 13.5 kDa subunit, representing the dimer of the 13.5 kDa subunit (PMID: 3008892). Deficiency of MPO is the cause of myeloperoxidase deficiency (MPOD). It has three isoforms generated by alternative splicing. This antibody is specific for MPO virus.
