IUBMB Enzyme Nomenclature


Accepted name: [histone H3]-lysine9 N-trimethyltransferase

Reaction: 3 S-adenosyl-L-methionine + a [histone H3]-L-lysine9 = 3 S-adenosyl-L-homocysteine + a [histone H3]-N6,N6,N6-trimethyl-L-lysine9 (overall reaction)
(1a) S-adenosyl-L-methionine + a [histone H3]-L-lysine9 = S-adenosyl-L-homocysteine + a [histone H3]-N6-methyl-L-lysine9
(1b) S-adenosyl-L-methionine + a [histone H3]-N6-methyl-L-lysine9 = S-adenosyl-L-homocysteine + a [histone H3]-N6,N6-dimethyl-L-lysine9
(1c) S-adenosyl-L-methionine + a [histone H3]-N6,N6-dimethyl-L-lysine9 = S-adenosyl-L-homocysteine + a [histone H3]-N6,N6,N6-trimethyl-L-lysine9

Other name(s): KMT1A (gene name); KMT1B (gene name); KMT1C (gene name); KMT1D (gene name); KMT1F (gene name); MT8 (gene name); SUV39H1 (gene name); G9A (gene name); EHMT1 (gene name); PRDM2 (gene name)

Systematic name: S-adenosyl-L-methionine:[histone H3]-L-lysine9 N6-trimethyltransferase

Comments: This entry describes several enzymes that successively methylate the L-lysine9 residue of histone H3 (H3K9), ultimately generating a trimethylated form. These modifications influence the binding of chromatin-associated proteins. In general, the methylation of H3K9 leads to transcriptional repression of the affected target genes. cf. EC, [histone H3]-lysine9 N-methyltransferase, EC, [histone H3]-lysine9 N-dimethyltransferase, and EC, [histone H3]-N6,N6-dimethyl-lysine9 N-methyltransferase.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc PDB, CAS registry number:


1. O'Carroll, D., Scherthan, H., Peters, A.H., Opravil, S., Haynes, A.R., Laible, G., Rea, S., Schmid, M., Lebersorger, A., Jerratsch, M., Sattler, L., Mattei, M.G., Denny, P., Brown, S.D., Schweizer, D. and Jenuwein, T. Isolation and characterization of Suv39h2, a second histone H3 methyltransferase gene that displays testis-specific expression. Mol. Cell Biol. 20 (2000) 9423-9433. [PMID: 11094092]

2. Schotta, G., Ebert, A., Krauss, V., Fischer, A., Hoffmann, J., Rea, S., Jenuwein, T., Dorn, R. and Reuter, G. Central role of Drosophila SU(VAR)3-9 in histone H3-K9 methylation and heterochromatic gene silencing. EMBO J. 21 (2002) 1121-1131. [PMID: 11867540]

3. Tachibana, M., Sugimoto, K., Nozaki, M., Ueda, J., Ohta, T., Ohki, M., Fukuda, M., Takeda, N., Niida, H., Kato, H. and Shinkai, Y. G9a histone methyltransferase plays a dominant role in euchromatic histone H3 lysine 9 methylation and is essential for early embryogenesis. Genes Dev. 16 (2002) 1779-1791. [PMID: 12130538]

4. Schultz, D.C., Ayyanathan, K., Negorev, D., Maul, G.G. and Rauscher, F.J., 3rd. SETDB1: a novel KAP-1-associated histone H3, lysine 9-specific methyltransferase that contributes to HP1-mediated silencing of euchromatic genes by KRAB zinc-finger proteins. Genes Dev. 16 (2002) 919-932. [PMID: 11959841]

5. Kim, K.C., Geng, L. and Huang, S. Inactivation of a histone methyltransferase by mutations in human cancers. Cancer Res. 63 (2003) 7619-7623. [PMID: 14633678]

6. Wu, H., Min, J., Lunin, V.V., Antoshenko, T., Dombrovski, L., Zeng, H., Allali-Hassani, A., Campagna-Slater, V., Vedadi, M., Arrowsmith, C.H., Plotnikov, A.N. and Schapira, M. Structural biology of human H3K9 methyltransferases. PLoS One 5 (2010) e8570. [PMID: 20084102]

[EC created 1976 as EC, modified 1982, modified 1983, part transferred 2019 to EC, modified 2020]

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