Q9UWY8 · SPEH_SACS2
- 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. Has no arginine decarboxylase (ArgDC) activity.
Miscellaneous
A chimeric protein containing the beta subunit of SSO0536 and the alpha subunit of SSO0585 (SpeH) has ArgDC activity and no AdoMetDC activity, implicating residues responsible for substrate specificity in the beta subunit. But additional factors in the alpha subunit are required for efficient cleavage and turnover.
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. Irreversibly inhibited by NaBH4 in vitro.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
96 μM | S-adenosyl-L-methionine |
pH Dependence
Optimum pH is 7.4.
Temperature Dependence
Optimum temperature is 75 degrees Celsius. Thermostable. Retains 20% activity after incubation at 100 degrees Celsius for 1 hour, 80% after 16 hours at 70 degrees Celsius, while no loss of activity is observed after 16 hours at 50 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 | 70-71 | Cleavage (non-hydrolytic); by autolysis | ||||
Sequence: ES | ||||||
Active site | 71 | Schiff-base intermediate with substrate; via pyruvic acid | ||||
Sequence: S | ||||||
Active site | 76 | Proton acceptor; for processing activity | ||||
Sequence: H | ||||||
Active site | 91 | 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 > Thermoproteota > Thermoprotei > Sulfolobales > Sulfolobaceae > Saccharolobus
Accessions
- Primary accessionQ9UWY8
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
PTM/Processing
Features
Showing features for chain, modified residue.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000030151 | 1-70 | S-adenosylmethionine decarboxylase beta chain | |||
Sequence: MMMGVELAFPKVVGKQVYGSLYECDEDVLKDTKRLEQIIKEAADIGNMNILDIKSWKIGEGVSVVAIILE | ||||||
Modified residue | 71 | Pyruvic acid (Ser); by autocatalysis | ||||
Sequence: S | ||||||
Chain | PRO_0000030152 | 71-124 | S-adenosylmethionine decarboxylase alpha chain | |||
Sequence: SHITIHTWPEYRFATVDVYSCGPHTSPLNAFRYIVEKLGAKRYTINEADRSSEF |
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)14,044
- Last updated2000-05-01 v1
- Checksum002511155E18D68A
Mass Spectrometry
S-adenosylmethionine decarboxylase alpha chain
Molecular mass is 6,258 Da. Determined by Electrospray. Pyruvoyl group-containing alpha subunit.Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
Y18930 EMBL· GenBank· DDBJ | CAB57715.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AE006641 EMBL· GenBank· DDBJ | AAK40898.1 EMBL· GenBank· DDBJ | Genomic DNA |