IUBMB Enzyme Nomenclature


Accepted name: peptide chain release factor N5-glutamine methyltransferase

Reaction: S-adenosyl-L-methionine + [peptide chain release factor 1 or 2]-L-glutamine = S-adenosyl-L-homocysteine + [peptide chain release factor 1 or 2]-N5-methyl-L-glutamine

Other name(s): N5-glutamine S-adenosyl-L-methionine dependent methyltransferase; N5-glutamine MTase; HemK; PrmC

Systematic name: S-adenosyl-L-methionine:[peptide chain release factor 1 or 2]-L-glutamine (N5-glutamine)-methyltransferase

Comments: Modifies the glutamine residue in the universally conserved glycylglycylglutamine (GGQ) motif of peptide chain release factor, resulting in almost complete loss of release activity.

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


1. Nakahigashi, K., Kubo, N., Narita, S., Shimaoka, T., Goto, S., Oshima, T., Mori, H., Maeda, M., Wada, C. and Inokuchi, H. HemK, a class of protein methyl transferase with similarity to DNA methyl transferases, methylates polypeptide chain release factors, and hemK knockout induces defects in translational termination. Proc. Natl. Acad. Sci. USA 99 (2002) 1473-1478. [PMID: 11805295]

2. Heurgue-Hamard, V., Champ, S., Engstrom, A., Ehrenberg, M. and Buckingham, R.H. The hemK gene in Escherichia coli encodes the N5-glutamine methyltransferase that modifies peptide release factors. EMBO J. 21 (2002) 769-778. [PMID: 11847124]

3. Schubert, H.L., Phillips, J.D. and Hill, C.P. Structures along the catalytic pathway of PrmC/HemK, an N5-glutamine AdoMet-dependent methyltransferase. Biochemistry 42 (2003) 5592-5599. [PMID: 12741815]

4. Yoon, H.J., Kang, K.Y., Ahn, H.J., Shim, S.M., Ha, J.Y., Lee, S.K., Mikami, B. and Suh, S.W. X-ray crystallographic studies of HemK from Thermotoga maritima, an N5-glutamine methyltransferase. Mol. Cells 16 (2003) 266-269. [PMID: 14651272]

5. Yang, Z., Shipman, L., Zhang, M., Anton, B.P., Roberts, R.J. and Cheng, X. Structural characterization and comparative phylogenetic analysis of Escherichia coli HemK, a protein (N5)-glutamine methyltransferase. J. Mol. Biol. 340 (2004) 695-706. [PMID: 15223314]

6. Pannekoek, Y., Heurgue-Hamard, V., Langerak, A.A., Speijer, D., Buckingham, R.H. and van der Ende, A. The N5-glutamine S-adenosyl-L-methionine-dependent methyltransferase PrmC/HemK in Chlamydia trachomatis methylates class 1 release factors. J. Bacteriol. 187 (2005) 507-511. [PMID: 15629922]

[EC created 2014]

Return to EC 2.1.1 home page
Return to EC 2.1 home page
Return to EC 2 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page