The JARID1B Chemiluminescent Assay Kit is designed to measure JARID1B activity for screening and profiling applications. JARID1B is a member of the Jumonji, AT-rich interactive domain 1 (JARID1) histone demethylase protein family. It binds directly, with several other proteins, to retinoblastoma protein which regulates cell proliferation. The key to the JARID1B Chemiluminescent Assay Kit is a highly specific antibody that recognizes demethylated substrate. With this kit, only three simple steps on a microtiter plate are required for detection of demethylase activity. First, JARID1B enzyme is incubated with the methylated H3 peptide for one hour. Next, primary antibody is added. Finally, the plate is treated with an HRP-labeled secondary antibody followed by the addition of the HRP substrate to produce chemiluminescence that can be measured using a chemiluminescence reader.