Q9UWY8 · SPEH_SACS2

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

Cofactor

pyruvate (UniProtKB | Rhea| CHEBI:15361 )

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 μMS-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.

TypeIDPosition(s)Description
Site70-71Cleavage (non-hydrolytic); by autolysis
Active site71Schiff-base intermediate with substrate; via pyruvic acid
Active site76Proton acceptor; for processing activity
Active site91Proton donor; for catalytic activity

GO annotations

AspectTerm
Cellular Componentcytosol
Molecular Functionadenosylmethionine decarboxylase activity
Biological Processspermidine biosynthetic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

Gene names

    • Name
      speH
    • ORF names
      C21_014
    • Ordered locus names
      SSO0585

Organism names

Accessions

  • Primary accession
    Q9UWY8

Proteomes

Subcellular Location

PTM/Processing

Features

Showing features for chain, modified residue.

TypeIDPosition(s)Description
ChainPRO_00000301511-70S-adenosylmethionine decarboxylase beta chain
Modified residue71Pyruvic acid (Ser); by autocatalysis
ChainPRO_000003015271-124S-adenosylmethionine decarboxylase alpha chain

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

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

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Sequence processing
    The displayed sequence is further processed into a mature form.
  • Length
    124
  • Mass (Da)
    14,044
  • Last updated
    2000-05-01 v1
  • Checksum
    002511155E18D68A
MMMGVELAFPKVVGKQVYGSLYECDEDVLKDTKRLEQIIKEAADIGNMNILDIKSWKIGEGVSVVAIILESHITIHTWPEYRFATVDVYSCGPHTSPLNAFRYIVEKLGAKRYTINEADRSSEF

Mass Spectrometry

S-adenosylmethionine decarboxylase alpha chain

Molecular mass is 6,258 Da. Determined by Electrospray. Pyruvoyl group-containing alpha subunit.

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
Y18930
EMBL· GenBank· DDBJ
CAB57715.1
EMBL· GenBank· DDBJ
Genomic DNA
AE006641
EMBL· GenBank· DDBJ
AAK40898.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

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