Cayman’s MPO Peroxidation Fluorometric Assay provides a convenient fluorescence-based method for detecting MPO peroxidase activity in both crude cell lysates and purified enzyme preparations. The assay utilizes the peroxidase component of MPO. The reaction between hydrogen peroxide and 10-acetyl-3,7-dihydroxyphenoxazine (ADHP) produces the highly fluorescent compound resorufin. Resorufin fluorescence is analyzed with an excitation wavelength between 530-540 nm and emission wavelength between 585-595 nm. The kit includes an MPO-specific inhibitor for distinguishing MPO activity from MPO-independent fluroescence.