A potent, peptide-competitive inhibitor of the lysine methyltransferase G9a (IC50 = 3.3 nM); significantly reduces the cellular levels of dimethylation on histone 3 at lysine 9 (H3K9Me2) in PC3 cells; also blocks the interaction of Spindlin1 with H3K4me3 by binding with a Spindlin1 Tudor domain (Kd = 111 nM).