Q57763 · SPEH_METJA
- ProteinS-adenosylmethionine decarboxylase proenzyme
- GenespeH
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids124 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Catalyzes the decarboxylation of S-adenosylmethionine to S-adenosylmethioninamine (dcAdoMet), the propylamine donor required for the synthesis of the polyamines spermine and spermidine from the diamine putrescine.
Catalytic activity
- H+ + S-adenosyl-L-methionine = CO2 + S-adenosyl 3-(methylsulfanyl)propylamine
Cofactor
Note: Binds 1 pyruvoyl group covalently per subunit.
Activity regulation
Competitively inhibited by methylglyoxal bis-guanylhydrazone. Inactivated by treatment with the imine reductant NaCNBH3 only in the presence of substrate.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
95 μM | S-adenosyl-L-methionine | 7.5 | 22 |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
37 nmol/min/mg | 7.5 | 22 |
The turnover number increases 30-fold when temperature is increased from 22 to 70 degrees Celsius, whereas the Km increases 3-fold.
pH Dependence
Optimum pH is 6-8.
Temperature Dependence
Optimum temperature is superior to 90 degrees Celsius. Thermostable. Retains full activity after 3 hours at 70 degrees Celsius.
Pathway
Amine and polyamine biosynthesis; S-adenosylmethioninamine biosynthesis; S-adenosylmethioninamine from S-adenosyl-L-methionine: step 1/1.
Features
Showing features for site, active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Site | 63-64 | Cleavage (non-hydrolytic); by autolysis | ||||
Sequence: ES | ||||||
Active site | 64 | Schiff-base intermediate with substrate; via pyruvic acid | ||||
Sequence: S | ||||||
Active site | 69 | Proton acceptor; for processing activity | ||||
Sequence: H | ||||||
Active site | 84 | Proton donor; for catalytic activity | ||||
Sequence: C |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytosol | |
Molecular Function | adenosylmethionine decarboxylase activity | |
Biological Process | spermidine biosynthetic process |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameS-adenosylmethionine decarboxylase proenzyme
- EC number
- Short namesAdoMetDC; SAMDC
- Cleaved into 2 chains
Gene names
Organism names
- Strain
- Taxonomic lineageArchaea > Euryarchaeota > Methanomada group > Methanococci > Methanococcales > Methanocaldococcaceae > Methanocaldococcus
Accessions
- Primary accessionQ57763
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
PTM/Processing
Features
Showing features for chain, modified residue.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000030133 | 1-63 | S-adenosylmethionine decarboxylase beta chain | |||
Sequence: MLKYLGKHLILELWGCDPKALDDIEGIEKMLVDSVKACGATLICVRTHKFSPQGATGVAVLAE | ||||||
Modified residue | 64 | Pyruvic acid (Ser); by autocatalysis | ||||
Sequence: S | ||||||
Chain | PRO_0000030134 | 64-124 | S-adenosylmethionine decarboxylase alpha chain | |||
Sequence: SHIAIHTYPEYGYAALDVFTCGEHTDPYKALEVIREFLKPKSIQIIDLKRGLMENGTFELK |
Post-translational modification
Is synthesized initially as an inactive proenzyme. Formation of the active enzyme involves a self-maturation process in which the active site pyruvoyl group is generated from an internal serine residue via an autocatalytic post-translational modification. Two non-identical subunits are generated from the proenzyme in this reaction, and the pyruvate is formed at the N-terminus of the alpha chain, which is derived from the carboxyl end of the proenzyme. The post-translation cleavage follows an unusual pathway, termed non-hydrolytic serinolysis, in which the side chain hydroxyl group of the serine supplies its oxygen atom to form the C-terminus of the beta chain, while the remainder of the serine residue undergoes an oxidative deamination to produce ammonia and the pyruvoyl group blocking the N-terminus of the alpha chain.
Keywords
- PTM
Proteomic databases
Interaction
Subunit
Heterotetramer of two alpha and two beta chains arranged as a dimer of alpha/beta heterodimers.
Protein-protein interaction databases
Structure
Family & Domains
Sequence similarities
Belongs to the prokaryotic AdoMetDC family. Type 1 subfamily.
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length124
- Mass (Da)13,792
- Last updated2001-08-14 v2
- ChecksumBC1152CDE080F113
Sequence caution
Mass Spectrometry
S-adenosylmethionine decarboxylase beta chain
Molecular mass is 6,793.1 Da. Determined by MALDI.S-adenosylmethionine decarboxylase alpha chain
Molecular mass is 6,990.2 Da. Determined by MALDI. Pyruvoyl group-containing alpha subunit.Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
L77117 EMBL· GenBank· DDBJ | AAB98301.1 EMBL· GenBank· DDBJ | Genomic DNA | Different initiation |