Histone-lysine N-methyltransferase EZH2  is a methyltransferase involved in transcriptional gene regulation. Together with with EED, RbAP48, SUZ12 and AEBP2, EZH2 forms a 5-member complex that adds 3 methyl groups to Lysine 27 of Histone H3 (H3K27). EZH2 acts on chromatin condensation and gene transcription activity.