| IPR019954 | Ubiquitin conserved site | Conserved Site |
| IPR050158 | Ubiquitin and ubiquitin-like | Family |
| IPR000626 | Ubiquitin-like domain | Domain |
| IPR019956 | Ubiquitin domain | Domain |
| IPR029071 | Ubiquitin-like domain superfamily | Homologous Superfamily |
| IPR057733 | UBE2O-like, SH3-B domain | Domain |
| IPR057732 | UBE2O, N-terminal SH3-A domain | Domain |
| IPR016135 | Ubiquitin-conjugating enzyme/RWD-like | Homologous Superfamily |
| IPR057734 | UBE2O-like, SH3-C domain | Domain |
| IPR000608 | Ubiquitin-conjugating (UBC), catalytic core domain | Domain |
| IPR057735 | UBE2O-like, tandem tSH3-B domain | Domain |
| IPR042302 | Ubiquitin-activating enzyme E1, FCCH domain superfamily | Homologous Superfamily |
| IPR045886 | ThiF/MoeB/HesA family | Family |
| IPR042449 | Ubiquitin-activating enzyme E1, inactive adenylation domain, subdomain 1 | Homologous Superfamily |
| IPR019572 | Ubiquitin-activating enzyme, SCCH domain | Domain |
| IPR018075 | Ubiquitin-activating enzyme E1 | Family |
| IPR032418 | Ubiquitin-activating enzyme E1, FCCH domain | Domain |
| IPR000011 | Ubiquitin/SUMO-activating enzyme E1-like | Family |
| IPR042063 | Ubiquitin-activating enzyme E1, SCCH domain | Homologous Superfamily |
| IPR000594 | THIF-type NAD/FAD binding fold | Domain |
| IPR032420 | Ubiquitin-activating enzyme E1, four-helix bundle | Domain |
| IPR018965 | Ubiquitin-activating enzyme E1, C-terminal | Domain |
| IPR035985 | Ubiquitin-activating enzyme-like | Homologous Superfamily |
| IPR033127 | Ubiquitin-activating enzyme E1, Cys active site | Active Site |
| IPR038252 | Ubiquitin-activating enzyme E1, C-terminal domain superfamily | Homologous Superfamily |
| IPR018074 | Ubiquitin-activating enzyme E1, conserved site | Conserved Site |