IUBMB Enzyme Nomenclature


Accepted name: N-terminal E2 ubiquitin-conjugating enzyme

Reaction: S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [acceptor protein]-N-terminal-amino acid = [E1 ubiquitin-activating enzyme]-L-cysteine + N-terminal-ubiquitinyl-[acceptor protein] (overall reaction)
(1a) S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [N-terminal E2 ubiquitin-conjugating enzyme]-L-cysteine = [E1 ubiquitin-activating enzyme]-L-cysteine + S-ubiquitinyl-[N-terminal ubiquitin-conjugating enzyme]-L-cysteine
(1b) S-ubiquitinyl-[N-terminal E2 ubiquitin-conjugating E2 enzyme]-L-cysteine + [acceptor protein]-N-terminal-amino acid = [N-terminal E2 ubiquitin-conjugating enzyme]-L-cysteine + N-ubiquitinyl-[acceptor protein]-N-terminal amino acid

Other name(s): Ube2w; N-terminal ubiquitin-conjugating enzyme E2

Systematic name: S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine:acceptor protein ubiquitin ligase (peptide bond-forming)

Comments: The enzyme ubiquitinylates the N-terminus of the acceptor protein. It is not reactive towards free lysine.

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


1. Breitschopf, K., Bengal, E., Ziv, T., Admon, A. and Ciechanover, A. A novel site for ubiquitination: the N-terminal residue, and not internal lysines of MyoD, is essential for conjugation and degradation of the protein. EMBO J. 17 (1998) 5964-5973. [PMID: 9774340]

2. Tatham, M.H., Plechanovova, A., Jaffray, E.G., Salmen, H. and Hay, R.T. Ube2W conjugates ubiquitin to α-amino groups of protein N-termini. Biochem. J. 453 (2013) 137-145. [PMID: 23560854]

3. Scaglione, K.M., Basrur, V., Ashraf, N.S., Konen, J.R., Elenitoba-Johnson, K.S., Todi, S.V. and Paulson, H.L. The ubiquitin-conjugating enzyme (E2) Ube2w ubiquitinates the N terminus of substrates. J. Biol. Chem. 288 (2013) 18784-18788. [PMID: 23696636]

[EC created 2015]

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