Meprin α can cleave extracellular matrix proteins (pro-collagen I, fibronectin, osteopontin, SPARC), growth factors (VEGF-A, CTGF) and proteinases (MMP-1). Evidence has suggested that Meprin α is associated with cancer proliferation, cancer migration and invasion.The FRET substrate included in SensoLyte® 520 Meprin α Activity Assay Kit was designed to detect Meprin α activity and reduce the cross reactivity with Meprin β, ADAM10, α -secretase, BACE-2, ECEs and TACE. This assay kit can be used to detect enzyme activity in purified enzyme preparations and compound screening. Active Meprin α cleaves the FRET substrate, resulting in an increase of 5-FAM fluorescence, monitored at excitation/emission = 490 nm/520 nm. The long wavelength fluorescence of 5-FAM is also less interfered by the autofluorescence of components in biological samples and test compounds. This assay can detect as low as 0.1 ng/mL active Meprin α.The kit contains: •5-FAM/QXLᵀᴹ 520 Meprin α substrate, Ex/Em=490/520 nm upon cleavage• Assay buffer • Recombinant Human Meprin α• Meprin αactivation buffer• Meprin αstop solution• Inhibitor• Fluorescence reference standard for calibration • A detailed protocol Kit size: 100 assays (96-well plate)Figure 1.  Inhibition of Meprin α activity by Actinoninas measured with SensoLyte® 520 Meprin α Activity Assay Kit.