| Accepted Name |
|---|
| E1 SAMP-activating enzyme
|
| Alternative Name(s) |
|---|
| SAMP-activating enzyme E1 |
| Reaction catalysed |
|---|
| ATP + [SAMP]-Gly-Gly + [E1 SAMP-activating enzyme]-L-cysteine = S-[[SAMP]-Gly-Gly]-[[E1 SAMP-activating enzyme]-L-cysteine] + AMP + diphosphate |
| Comment(s) |
|---|
- The enzyme catalyzes the activation of SAMPs (Small Archaeal Modifier
Proteins), which are ubiquitin-like proteins found only in the
Archaea.
- SAMPs are involved in protein degradation, and also act as sulfur
carriers involved in thiolation of tRNA and other metabolites such as
molybdopterin.
- The enzyme catalyzes the ATP-dependent formation of a SAMP adenylate
intermediate in which the C-terminal glycine of SAMP is bound to AMP
via an acyl-phosphate linkage.
- This intermediate can accept a sulfur atom to form a thiocarboxylate
moiety in a mechanism that is not yet understood.
- Alternatively, the E1 enzyme can transfer SAMP from its activated
form to an internal cysteine residue, releasing AMP.
- In this case SAMP is subsequently transferred to a lysine residue in
a target protein in a process termed SAMPylation.
- Auto-SAMPylation (attachment of SAMP to lysine residues within the E1
enzyme) has been observed. cf. EC 2.7.7.100.
|
| Cross-references |
|---|
| BRENDA | 6.2.1.55 |
| EC2PDB | 6.2.1.55 |
| ExplorEnz | 6.2.1.55 |
| PRIAM enzyme-specific profiles | 6.2.1.55 |
| KEGG Ligand Database for Enzyme Nomenclature | 6.2.1.55 |
| IUBMB Enzyme Nomenclature | 6.2.1.55 |
| IntEnz | 6.2.1.55 |
| MEDLINE | Find literature relating to 6.2.1.55 |
| MetaCyc | 6.2.1.55 |
| Rhea expert-curated reactions | 6.2.1.55 |
View entry in original ENZYME format
View entry in raw text format (no links)
All
ENZYME /
UniProtKB/Swiss-Prot entries corresponding to 6.2.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.2.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.-.-.-