EC Number   |
Substrates |
Products  |
Reversibility |
|---|
   6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein UBE1]-L-cysteine |
- |
AMP + diphosphate + [ubiquitin-activating protein UBE1]-S-ubiquitinyl-L-cysteine |
- |
? |
| 6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein Uba6]-L-cysteine |
isoform Uba6 forms a covalent link with ubiquitin in vitro and in vivo, which is sensitive to reducing conditions. Recombinant E1 enzyme Uba6 can activate ubiquitin and transfer it onto the ubiquitin-conjugating enzyme UbcH5B. Ubiquitin activated by Uba6 can be used for ubiquitylation of p53 and supports the autoubiquitylation of the E3 ubiquitin ligases HectH9 and E6-AP |
AMP + diphosphate + [ubiquitin-activating protein Uba6]-S-ubiquitinyl-L-cysteine |
- |
? |
| 6.2.1.45 | ATP + Ufm1 + [ubiquitin-activating protein UBA5]-L-cysteine |
Ufm1, ubiquitin-fold modifier 1, an ubiquitin-like protein |
AMP + diphosphate + [ubiquitin-activating protein UBA5]-S-Ufm1-L-cysteine |
- |
? |
| 6.2.1.45 | ATP + SUMO2 + [ubiquitin-activating protein UBA5]-L-cysteine |
SUMO2, small ubiquitin-like modifier2, an ubiquitin-like protein |
AMP + diphosphate + [ubiquitin-activating protein UBA5]-S-SUMO2-L-cysteine |
enzyme greatly activates SUMO2 in the nucleus or transfers activated SUMO2 to the nucleus after it conjugated SUMO2 in the cytoplasm |
? |
| 6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein UBA2]-L-cysteine |
enzyme forms higher molecular mass intermediates with ubiquitin |
AMP + diphosphate + [ubiquitin-activating protein UBA2]-S-ubiquitinyl-L-cysteine |
the enzyme-ubiquitin intermediates dissociate in presence of 2-mercaptoethanol, indicating thiolester linkage |
? |
| 6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein UBA1]-L-cysteine |
enzyme forms higher molecular mass intermediates with ubiquitin |
AMP + diphosphate + [ubiquitin-activating protein UBA1]-S-ubiquitinyl-L-cysteine |
the enzyme-ubiquitin intermediates dissociate in presence of 2-mercaptoethanol, indicating thiolester linkage |
? |
| 6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein Uba1a]-L-cysteine |
- |
AMP + diphosphate + [ubiquitin-activating protein Uba1a]-S-ubiquitinyl-L-cysteine |
- |
? |
| 6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein E1]-L-cysteine |
a carboxylgroup is first activated as an adenylate followed by its direct transfer to an autonomous molecular moiety in a single enzymatic step |
AMP + diphosphate + [ubiquitin-activating protein E1]-S-ubiquitinyl-L-cysteine |
- |
? |
| 6.2.1.45 | ATP + ubiquitin + [ubiquitin-activating protein E1]-L-cysteine |
- |
AMP + diphosphate + [ubiquitin-activating protein E1]-S-ubiquitinyl-L-cysteine |
- |
? |
| 6.2.1.45 | ATP + ubiquitin mutant G76A + [ubiquitin-activating protein E1]-L-cysteine |
- |
AMP + diphosphate + [ubiquitin-activating protein E1]-S-(ubiquitin mutant G76A)yl-L-cysteine |
mutant ubiquitin G76A, bearing a Gly to Ala substitution at the COOH terminus is a substrate for El enzyme. Ubiquitin G76A supports PPI-ATP exchange with 500fold decrease in kcat/Km compared to wild-type ubiquitin, does not produce detectable AMP-Ub with native El, produces stoichiometric AMP-Ub with thiol-blocked El, gives a stoichiometric burst of ATP consumption with either native or thiol-blocked El, support El-ubiquitin thiol ester formation with native El, and supports several downstream reactions of the proteolytic pathway with a 20% decrease to the rate of wild type ubiquitin |
? |
