Description: The monoclonal antibody MPO455-8E6 recognizes myeloperoxidase (MPO), a protein within the azurophilic granules of myeloid cells. MPO is a multimeric protein comprised of two 55 kDa subunits and two 15 kDa subunits. The larger subunits associate with a heme protein resulting in a greenish color. As an enzyme, MPO breaks down hydrogen peroxide and oxidizes tyrosine. The products of this reaction, hypochlorous acid and tyrosyl radical, cause the cytotoxic and killing effects characteristic of neutrophils. Myeloperoxidase is important in the diagnosis of some cancers and increases in serum levels have been shown to correlate with cardiac events.