Ubiquitin/SUMO-activating enzyme E1 (IPR000011)

Short name: UBQ/SUMO-activ_enz_E1-like

Overlapping homologous superfamilies


Family relationships


The post-translational attachment of ubiquitin (IPR000626) to proteins (ubiquitinylation) alters the function, location or trafficking of a protein, or targets it to the 26S proteasome for degradation [PMID: 15556404, PMID: 15454246, PMID: 15196553]. Ubiquitinylation is an ATP-dependent process that involves the action of at least three enzymes: a ubiquitin-activating enzyme (E1), a ubiquitin-conjugating enzyme (E2, IPR000608), and a ubiquitin ligase (E3, IPR000569, IPR003613), which work sequentially in a cascade [PMID: 14998368]. The E1 enzyme is responsible for activating ubiquitin, the first step in ubiquitinylation. The E1 enzyme hydrolyses ATP and adenylates the C-terminal glycine residue of ubiquitin, and then links this residue to the active site cysteine of E1, yielding a ubiquitin-thioester and free AMP. To be fully active, E1 must non-covalently bind to and adenylate a second ubiquitin molecule. The E1 enzyme can then transfer the thioester-linked ubiquitin molecule to a cysteine residue on the ubiquitin-conjugating enzyme, E2, in an ATP-dependent reaction.

This entry also contains the SUMO activating enzyme E1.

GO terms

Biological Process

GO:0006464 cellular protein modification process

Molecular Function

GO:0008641 ubiquitin-like modifier activating enzyme activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.