Reaction Biology Corp. (ñRBCî) is a premier service provider for drug profiling, screening and early-stage drug discovery collaborations. Its proprietary HotSpot technology is an innovative platform for screening/profiling small molecules vs biological target assayable by radioisotope detection. For kinase and transferase enzymes in particular, such assays are the ñgold standardî. RBC screens and profiles vs all major classes of epigenetic transferases via the radioisotope approach„HMTs, DNMTs, HATs, and also over 600 kinases. HotSpot assay substrates require no special modifications (e.g. biotin, fluorophors or other tags). Hence biologically relevant substrates may be used, including full nucleosomes, histone proteins or peptides. Since detection does not rely on antibodies, coupling enzymes or fluorescence, major causes of false positives, false negatives and compound interference are eliminated. In 2016, Reaction Biology was awarded a NCI subcontract to help speed up drug discovery, and chosen as the preferred kinase service provider in HTStec's Kinase Profiling Trends Survey. Reaction Biology offers over 1000 targets for HTS and profiling. In addition to kinases and methyltransferases, RBC's offering includes over 100 reader domains, HDACs, demethylases, proteases, PARPs, and more. RBC also offers a line of high quality epigenetic proteins, including methyltransferases, reader domains, HDACs, and more. RBC develops and delivers recombinant HMT enzymes that are not only active but compatible with HTS assay conditions. The enzymes are fully validated for HTS and include some enzyme complexes are exclusive to RBC. RBC takes a comprehensive approach to serving the epigenetic drug discovery industry, providing high quality proteins, robust and low cost assay development, library screening, drug profiling , and validation of drug activity in cellular assays.