IUBMB Enzyme Nomenclature


Accepted name: N-terminal methionine Nα-acetyltransferase NatB

Reaction: (1) acetyl-CoA + an N-terminal L-methionyl-L-asparaginyl-[protein] = an N-terminal Nα-acetyl-L-methionyl-L-asparginyl-[protein] + CoA
(2) acetyl-CoA + an N-terminal L-methionyl-L-glutaminyl-[protein] = an N-terminal Nα-acetyl-L-methionyl-L-glutaminyl-[protein] + CoA
(3) acetyl-CoA + an N-terminal L-methionyl-L-aspartyl-[protein] = an N-terminal Nα-acetyl-L-methionyl-L-aspartyl-[protein] + CoA
(4) acetyl-CoA + an N-terminal L-methionyl-L-glutamyl-[protein] = an N-terminal Nα-acetyl-L-methionyl-L-glutamyl-[protein] + CoA

Other name(s): NAA20 (gene name); NAA25 (gene name)

Systematic name: acetyl-CoA:N-terminal Met-Asn/Gln/Asp/Glu-[protein] Met-Nα-acetyltransferase

Comments: N-terminal acetylases (NATs) catalyse the covalent attachment of an acetyl moiety from acetyl-CoA to the free α-amino group at the N-terminus of a protein. This irreversible modification neutralizes the positive charge at the N-terminus and makes the N-terminal residue larger and more hydrophobic, and may also play a role in membrane targeting and gene silencing. The NatB complex is found in all eukaryotic organisms, and specifically targets N-terminal L-methionine residues attached to Asn, Asp, Gln, or Glu residues at the second position.

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


1. Starheim, K.K., Arnesen, T., Gromyko, D., Ryningen, A., Varhaug, J.E. and Lillehaug, J.R. Identification of the human Nα-acetyltransferase complex B (hNatB): a complex important for cell-cycle progression. Biochem. J. 415 (2008) 325-331. [PMID: 18570629]

2. Ferrandez-Ayela, A., Micol-Ponce, R., Sanchez-Garcia, A.B., Alonso-Peral, M.M., Micol, J.L. and Ponce, M.R. Mutation of an Arabidopsis NatB N-α-terminal acetylation complex component causes pleiotropic developmental defects. PLoS One 8 (2013) e80697. [PMID: 24244708]

3. Lee, K.E., Ahn, J.Y., Kim, J.M. and Hwang, C.S. Synthetic lethal screen of NAA20, a catalytic subunit gene of NatB N-terminal acetylase in Saccharomyces cerevisiae. J Microbiol 52 (2014) 842-848. [PMID: 25163837]

[EC created 1989 as EC, part transferred 2016 to EC]

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