The TNKS1 Chemiluminescent Assay Kit is designed to measure the activity of Tankyrase 1 (TNKS1, also known as PARP5A) for screening and profiling applications. TNKS1 is known to catalyze the NAD-dependent ADP-ribosylation of histones. The key to the TNKS1 (PARP5A) Chemiluminescent Assay Kit is the biotinylated NAD+. With this kit, only three simple steps are required for TNKS1 reactions. First, histone proteins are coated on a 96-well or 384-well plate. Next, a biotinylated NAD+ mix (termed PARP Substrate Mixture) is incubated with the TNKS1 enzyme in an optimized assay buffer. Finally, the plate is treated with streptavidin-HRP followed by addition of the ELISA ECL substrate to produce chemiluminescence that can be measured using a chemiluminescence reader.*NOTE: As of April 2022, this protocol has been re-optimized for performance. Previous versions of this kit are available upon request.