The BRD3 (BD1) Inhibitor Screening Assay Kit is designed to measure the inhibition of BRD3 bromodomain 1 (BD1) from binding to its substrate. The key to the BRD3 (BD1) Inhibitor Screening Assay Kit is the highly specific binding of the BRD3 bromodomain 1 to the acetylated histone substrate. With this kit, only three simple steps on a microtiter plate are required. First, a sample containing BRD3 bromodomain 1 and an inhibitor of choice is incubated with the biotinylated substrate for thirty minutes. Next, acceptor beads are added, then donor beads, followed by reading the Alpha-counts.