Meprin β, a type I transmembrane metalloprotease, belongs to the astacin family of zinc endopeptidases and the metzincin superfamily. Protein expression has been identified in multiple tissues and cell types such as kidney, intestine, skin, leukocytes and several cancer cells. Though the biological function of Meprin β is not fully understood, it was found that Meprin β plays various roles in inflammatory response, collagen assembly, cancer progression and β-amyloid protein cleavage. More growing evidence has indicated that Meprin β is a good therapeutic target in regulating angiogenesis, cancer, inflammation, fibrosis, and neurodegenerative diseases.The SensoLyte® 520 Meprin β Activity Assay Kit can be used to detect enzyme activity in purified enzyme preparations and compound screening. The unique FRET substrate was derived from APP sequence designed to reduce the cross reactivity with Meprin α, ADAM10, α-secretase, BACE-2, IDE and ECEs, Neprilysin and TACE. Active Meprin β cleaves the FRET substrate resulting in an increase of 5-FAM fluorescence, that can be 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 0.048 ng/mL active Meprin β.The kit contains: •5-FAM/QXLᵀᴹ 520 Meprin β substrate, Ex/Em=490/520 nm upon cleavage• Assay buffer • Recombinant Human Meprin β• Meprin β activation buffer• Meprin β stop solution• Inhibitor• Fluorescence reference standard for calibration • A detailed protocol Kit size: 100 assays (96-well plate)Figure 1.Inhibition of Meprin β activity by Actinonin as measured with SensoLyte® 520 Meprin β Activity Assay Kit.