EC Number   |
Substrates |
Organism |
Products |
Reversibility |
|---|
   2.3.2.23 | more |
polyubiquitin chain formation catalyzed by E2 enzymes, in the absence of an E3 protein and a target protein substrate |
Homo sapiens |
? |
a thiol ester-linked ubiquitin to the E2 active site is an intermediate in any polyubiquination reactions |
? |
| 2.3.2.23 | more |
functional survey of 11 representative human E2 paralogs reveals similar Km values for binding to human Uba1 ternary complex with an average Km of 121 nM and kcat for ubiquitin transfer of 4.0 per s, suggesting that they possess a conserved binding site and transition state geometry and that they compete for charging through differences in intracellular concentration. This binding motif is localized to three basic residues within Helix 1 of the E2 core domain |
Homo sapiens |
? |
- |
? |
| 2.3.2.23 | more |
kinetics for Uba1a-catalyzed transthiolation of Ubc2b are used as a reporter assay for determining the Km and kcat values for the three cosubstrates of the ubiquitin-activating enzyme. The E2 transthiolation assays are more sensitive to the potential presence of trace catalytically active fragments than the single turnover end point assays used for quantitating ternary complex stoichiometry |
Homo sapiens |
? |
- |
? |
| 2.3.2.23 | more |
during transfer of ubiquitin to the final substrate or E3 ligase, reaction of EC 2.3.2.27, enzyme is restricted to monoubiquitinylation. UbcM2 shows enhanced polyubiquitin synthesizing activity in reaction mixtures containing ubiquitin mutant K48R. In contrast, reaction mixtures containing ubiquitin mutant K6R show a mild suppression of UbcM2 activity |
Homo sapiens |
? |
- |
? |
| 2.3.2.23 | more |
HECT-E3 ligase ETC-1 ubiquitylates securin IFY-1 and cyclin B1 in the presence of the E2 enzyme UBC-18 |
Caenorhabditis elegans |
? |
- |
? |
| 2.3.2.23 | more |
human liver endoplasmic reticulum-anchored cytochrome P450 enzyme CYP3A4 is degraded via ubiquitylation by E2 ubiquitin-conjugating enzyme UBC7/E3 ubiquitin-ligase gp78, reaction of EC 2.3.2.27. CYP3A4 Asp/Glu/Ser(P)/Thr(P) surface clusters are important for its intermolecular electrostatic interactions with each of these E2-E3 subcomponents. By imparting additional negative charge to these Asp/Glu clusters, such Ser/Thr phosphorylation would generate P450 phosphodegrons for molecular recognition by the E2-E3 complexes, thereby controlling the timing of CYP3A4 ubiquitination and endoplasmic reticulum-associated degradation |
Homo sapiens |
? |
- |
? |
| 2.3.2.23 | more |
the enzyme is nonreactive with free lysine |
Homo sapiens |
? |
- |
? |
| 2.3.2.23 | more |
determination of the E1 catalyzed E2-25K-Ub thioester conjugation reaction |
Homo sapiens |
? |
- |
- |
| 2.3.2.23 | more |
diubiquitin synthesis by enzyme UBE2R2 with 32P-labeled K48R donor ubiquitin and acceptor ubiquitin, which contains an additional Asp residue at its C-terminus (referred to as D77 ubiquitin, which cannot be thioesterified to Ube2R2), analysis of activities of wild-type Ube2R2 and mutants, D143K, D143R, D143A, and D91K, with wild-type ubiquitin and mutant ubiquitins, R54D, R54A, I44A, I44D, and D58R. The mutations reduce the activity, the combination of D143K enzyme with D58R ubiquitin is inactive, the mutation of Arg54 to an Asp residue in acceptor ubiquitin leads to a 52fold reduction in Ube2R2 activity compared with wild-type ubiquitin results. The Ube2R1/2 acidic loop participates in Lys48-specific polyubiquitin chain formation by binding to Skp1-cullin-Fbox (SCF), kinetics |
Homo sapiens |
? |
- |
- |
| 2.3.2.23 | more |
enzyme UBE2V1 and homologues are catalytically inactive E2-like proteins interacting with Ube2N for K63 chain formation. The enzyme interacts with ubiquitin, and with E3 ligases of types RING, and HECT (in combination with Ube2N). Whereas K63-specific Ube2N uses a tightly bound E2-like subunit (either Ube2V1 or Ube2V2) to position the K63 side chain of the incoming (acceptor) Ub |
Homo sapiens |
? |
- |
- |
