ID   DCAM_ACACA              Reviewed;          19 AA.
AC   P34039;
DT   01-FEB-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1994, sequence version 1.
DT   02-DEC-2020, entry version 70.
DE   RecName: Full=S-adenosylmethionine decarboxylase subunit alpha;
DE            Short=AdoMetDC;
DE            Short=SAMDC;
DE            EC=4.1.1.50;
DE   Flags: Fragment;
OS   Acanthamoeba castellanii (Amoeba).
OC   Eukaryota; Amoebozoa; Discosea; Longamoebia; Centramoebida;
OC   Acanthamoebidae; Acanthamoeba.
OX   NCBI_TaxID=5755;
RN   [1]
RP   PROTEIN SEQUENCE, PYRUVATE FORMATION AT SER-1, AND CHARACTERIZATION.
RX   PubMed=8216217; DOI=10.1042/bj2950203;
RA   Hugo E.R., Byers T.J.;
RT   "S-adenosyl-L-methionine decarboxylase of Acanthamoeba castellanii (Neff):
RT   purification and properties.";
RL   Biochem. J. 295:203-209(1993).
CC   -!- FUNCTION: S-adenosylmethionine decarboxylase is essential for the
CC       biosynthesis of spermine and spermidine. The alpha subunit contains the
CC       active site.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H(+) + S-adenosyl-L-methionine = CO2 + S-adenosyl 3-
CC         (methylsulfanyl)propylamine; Xref=Rhea:RHEA:15981, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:16526, ChEBI:CHEBI:57443, ChEBI:CHEBI:59789; EC=4.1.1.50;
CC   -!- COFACTOR:
CC       Name=pyruvate; Xref=ChEBI:CHEBI:15361;
CC       Note=Binds 1 pyruvoyl group covalently per subunit.;
CC   -!- PATHWAY: Amine and polyamine biosynthesis; S-adenosylmethioninamine
CC       biosynthesis; S-adenosylmethioninamine from S-adenosyl-L-methionine:
CC       step 1/1.
CC   -!- SUBUNIT: Heterotetramer of two alpha and two beta chains.
CC   -!- DEVELOPMENTAL STAGE: Expressed only during exponential growth.
CC   -!- INDUCTION: Stimulated by putrescine. Inhibited by aromatic diamidines
CC       berenil, pentamidine, propamidine, hydroxystilbamidine, by ethidium
CC       bromide and methylglyoxal.
CC   -!- PTM: Is synthesized initially as an inactive proenzyme. Formation of
CC       the active enzyme involves a self-maturation process in which the
CC       active site pyruvoyl group is generated from an internal serine residue
CC       via an autocatalytic post-translational modification. Two non-identical
CC       subunits are generated from the proenzyme in this reaction, and the
CC       pyruvate is formed at the N-terminus of the alpha chain, which is
CC       derived from the carboxyl end of the proenzyme. The post-translation
CC       cleavage follows an unusual pathway, termed non-hydrolytic serinolysis,
CC       in which the side chain hydroxyl group of the serine supplies its
CC       oxygen atom to form the C-terminus of the beta chain, while the
CC       remainder of the serine residue undergoes an oxidative deamination to
CC       produce ammonia and the pyruvoyl group blocking the N-terminus of the
CC       alpha chain (By similarity). {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the eukaryotic AdoMetDC family. {ECO:0000305}.
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DR   PIR; S38763; S38763.
DR   UniPathway; UPA00331; UER00451.
DR   GO; GO:0004014; F:adenosylmethionine decarboxylase activity; IEA:UniProtKB-EC.
DR   GO; GO:0006557; P:S-adenosylmethioninamine biosynthetic process; IEA:UniProtKB-UniPathway.
DR   GO; GO:0008295; P:spermidine biosynthetic process; IEA:UniProtKB-KW.
DR   GO; GO:0006597; P:spermine biosynthetic process; IEA:InterPro.
DR   InterPro; IPR001985; S-AdoMet_decarboxylase.
DR   InterPro; IPR016067; S-AdoMet_deCO2ase_core.
DR   Pfam; PF01536; SAM_decarbox; 1.
DR   SUPFAM; SSF56276; SSF56276; 1.
PE   1: Evidence at protein level;
KW   Autocatalytic cleavage; Decarboxylase; Direct protein sequencing; Lyase;
KW   Polyamine biosynthesis; Pyruvate; S-adenosyl-L-methionine; Schiff base;
KW   Spermidine biosynthesis.
FT   CHAIN           1..>19
FT                   /note="S-adenosylmethionine decarboxylase subunit alpha"
FT                   /id="PRO_0000157475"
FT   ACT_SITE        1
FT                   /note="Schiff-base intermediate with substrate; via pyruvic
FT                   acid"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        15
FT                   /note="Proton donor; for catalytic activity"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         1
FT                   /note="Pyruvic acid (Ser); by autocatalysis"
FT                   /evidence="ECO:0000269|PubMed:8216217"
FT   NON_TER         19
SQ   SEQUENCE   19 AA;  2154 MW;  88B18AD9B6142AEF CRC64;
     SSMFVWNTKL ILKTCGTXL