ENZYME entry: EC 18.104.22.168
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|E1 SAMP-activating enzyme.
|SAMP-activating enzyme E1.|
|ATP + [SAMP]-Gly-Gly + [E1 SAMP-activating enzyme]-L-cysteine <=> S-([SAMP]-Gly-Gly)-([E1 SAMP-activating enzyme]-L-cysteine) + AMP + diphosphate|
- The enzyme catalyzes the activation of SAMPs (Small Archaeal Modifier
Proteins), which are ubiquitin-like proteins found only in the
- SAMPs are involved in protein degradation, and also act as sulfur
carriers involved in thiolation of tRNA and other metabolites such as
- 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 22.214.171.124.
|PRIAM enzyme-specific profiles||126.96.36.199|
|KEGG Ligand Database for Enzyme Nomenclature||188.8.131.52|
|IUBMB Enzyme Nomenclature||184.108.40.206|
|MEDLINE||Find literature relating to 220.127.116.11|
entries corresponding to 6.2.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.2.-.-
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