SET Domain-containing Protein 8 is a MT that selectively mono-methylates histone H4 at lysine residue 20 (H4K20), an event proven to have an important role in chromatin structure and transcriptional activation. Cayman's SET8 MT Inhibitor Screening Assay provides a convenient method for screening human SET8 inhibitors. The transfer of the methyl group from SAM by SET8 (provided in the kit) to the acceptor peptide (H4K20) generates S-adenosylhomocysteine, which is rapidly converted to urate and H2O2 using an enzyme mixture provided in the kit. The H2O2 formed reacts with ADHP (10-acetyl-3,7-dihydroxyphenoxazine) to produce the highly fluorescent compound resorufin (excitation 530-540 nm; emission 585-595 nm).