IUBMB Enzyme Nomenclature


Accepted name: histone H4 N-methyl-L-lysine20 N-methyltransferase

Reaction: S-adenosyl-L-methionine + a [histone H4]-N6-methyl-L-lysine20 = S-adenosyl-L-homocysteine + a [histone H4]-N6,N6-dimethyl-L-lysine20

Other name(s): KMT5B (gene name); KMT5C (gene name); SUV420H1 (gene name); SUV420H2 (gene name)

Systematic name: S-adenosyl-L-methionine:[histone H4]-N6-methyl-L-lysine20 N6-methyltransferase

Comments: This entry describes a group of enzymes that catalyse a single methylation of monomethylated lysine 20 of histone H4 (H4K20m1, generated by EC, histone H4 lysine20 N-methyltransferase), forming the dimethylated form. This modification is broadly distributed across the genome and is likely important for general chromatin-mediated processes. The double-methylated form of lysine20 in histone H4 is the most abundant methylation state of this residue and is found on ~80% of all histone H4 molecules. Full activity of the enzyme requires that the lysine at position 9 of histone H3 is trimethylated.

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


1. Schotta, G., Lachner, M., Sarma, K., Ebert, A., Sengupta, R., Reuter, G., Reinberg, D. and Jenuwein, T. A silencing pathway to induce H3-K9 and H4-K20 trimethylation at constitutive heterochromatin. Genes Dev. 18 (2004) 1251-1262. [PMID: 15145825]

2. Jorgensen, S., Schotta, G. and Sorensen, C.S. Histone H4 lysine 20 methylation: key player in epigenetic regulation of genomic integrity. Nucleic Acids Res. 41 (2013) 2797-2806. [PMID: 23345616]

3. Wu, H., Siarheyeva, A., Zeng, H., Lam, R., Dong, A., Wu, X.H., Li, Y., Schapira, M., Vedadi, M. and Min, J. Crystal structures of the human histone H4K20 methyltransferases SUV420H1 and SUV420H2. FEBS Lett. 587 (2013) 3859-3868. [PMID: 24396869]

4. Southall, S.M., Cronin, N.B. and Wilson, J.R. A novel route to product specificity in the Suv4-20 family of histone H4K20 methyltransferases. Nucleic Acids Res. 42 (2014) 661-671. [PMID: 24049080]

5. Weirich, S., Kudithipudi, S. and Jeltsch, A. Specificity of the SUV4-20H1 and SUV4-20H2 protein lysine methyltransferases and methylation of novel substrates. J. Mol. Biol. 428 (2016) 2344-2358. [PMID: 27105552]

[EC created 2019]

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