ID   SAHH_MESCR              Reviewed;         485 AA.
AC   P93253;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1997, sequence version 1.
DT   02-SEP-2026, entry version 107.
DE   RecName: Full=Adenosylhomocysteinase;
DE            Short=AdoHcyase;
DE            EC=3.13.2.1;
DE   AltName: Full=S-adenosyl-L-homocysteine hydrolase;
GN   Name=SAHH;
OS   Mesembryanthemum crystallinum (Common ice plant) (Cryophytum crystallinum).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   Caryophyllales; Aizoaceae; Mesembryanthemum;
OC   Mesembryanthemum subgen. Cryophytum.
OX   NCBI_TaxID=3544;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RA   Michalowski C.B., Bohnert H.J.;
RL   Submitted (NOV-1996) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Adenosylhomocysteine is a competitive inhibitor of S-
CC       adenosyl-L-methionine-dependent methyl transferase reactions; therefore
CC       adenosylhomocysteinase may play a key role in the control of
CC       methylations via regulation of the intracellular concentration of
CC       adenosylhomocysteine. {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=S-adenosyl-L-homocysteine + H2O = L-homocysteine + adenosine;
CC         Xref=Rhea:RHEA:21708, ChEBI:CHEBI:15377, ChEBI:CHEBI:16335,
CC         ChEBI:CHEBI:57856, ChEBI:CHEBI:58199; EC=3.13.2.1;
CC   -!- COFACTOR:
CC       Name=NAD(+); Xref=ChEBI:CHEBI:57540;
CC       Note=Binds 1 NAD(+) per subunit.;
CC   -!- PATHWAY: Amino-acid biosynthesis; L-homocysteine biosynthesis; L-
CC       homocysteine from S-adenosyl-L-homocysteine: step 1/1.
CC   -!- SUBUNIT: Homotetramer. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the adenosylhomocysteinase family.
CC       {ECO:0000305}.
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DR   EMBL; U79766; AAB38499.1; -; mRNA.
DR   AlphaFoldDB; P93253; -.
DR   SMR; P93253; -.
DR   UniPathway; UPA00314; UER00076.
DR   GO; GO:0005829; C:cytosol; IEA:TreeGrafter.
DR   GO; GO:0004013; F:adenosylhomocysteinase activity; IEA:UniProtKB-EC.
DR   GO; GO:0033353; P:L-methionine cycle; IEA:TreeGrafter.
DR   CDD; cd00401; SAHH; 1.
DR   FunFam; 3.40.50.720:FF:000004; Adenosylhomocysteinase; 1.
DR   Gene3D; 3.40.50.1480; Adenosylhomocysteinase-like; 1.
DR   Gene3D; 3.40.50.720; NAD(P)-binding Rossmann-like Domain; 1.
DR   HAMAP; MF_00563; AdoHcyase; 1.
DR   InterPro; IPR042172; Adenosylhomocyst_ase-like_sf.
DR   InterPro; IPR000043; Adenosylhomocysteinase-like.
DR   InterPro; IPR015878; Ado_hCys_hydrolase_NAD-bd.
DR   InterPro; IPR036291; NAD(P)-bd_dom_sf.
DR   InterPro; IPR020082; S-Ado-L-homoCys_hydrolase_CS.
DR   NCBIfam; TIGR00936; ahcY; 1.
DR   NCBIfam; NF004005; PRK05476.2-3; 1.
DR   PANTHER; PTHR23420; ADENOSYLHOMOCYSTEINASE; 1.
DR   PANTHER; PTHR23420:SF0; ADENOSYLHOMOCYSTEINASE; 1.
DR   Pfam; PF05221; AdoHcyase; 1.
DR   Pfam; PF00670; AdoHcyase_NAD; 1.
DR   PIRSF; PIRSF001109; Ad_hcy_hydrolase; 1.
DR   SMART; SM00996; AdoHcyase; 1.
DR   SMART; SM00997; AdoHcyase_NAD; 1.
DR   SUPFAM; SSF52283; Formate/glycerate dehydrogenase catalytic domain-like; 2.
DR   SUPFAM; SSF51735; NAD(P)-binding Rossmann-fold domains; 1.
DR   PROSITE; PS00738; ADOHCYASE_1; 1.
DR   PROSITE; PS00739; ADOHCYASE_2; 1.
PE   2: Evidence at transcript level;
KW   Hydrolase; NAD; One-carbon metabolism.
FT   CHAIN           1..485
FT                   /note="Adenosylhomocysteinase"
FT                   /id="PRO_0000116926"
FT   BINDING         64
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         139
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         205
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         206..208
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         235
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         239
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         240
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         269..274
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         292
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         327
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   BINDING         348..350
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   485 AA;  53178 MW;  2C3B339BD4F7BAE6 CRC64;
     MALAVEKTSS GREYKVKDMS QADFGRLEIE LAEVEMPGLM ACRTEFGPSQ PFKGAKITGS
     LHMTIQTAVL IETLTALGAE VRWCSCNIFS TQDHAAAAIA RDSAAVFAWK GETLQEYWWC
     TERALDWGAG GGPDLIVDDG GDATLLIHEG VKAEEEYEKN GTIPDPTSTD NPEFQLVLGL
     IRDSLKVDPK RYHKMKTRLV GVSEETTTGV KRLYQMQATG TLLFPAINVN DSVTKSKFDN
     LYGCRHSLPD GLMRATDVMI AGKVGVVCGY GDVGKGCALA LKAAGARVIV TEIDPICALQ
     ALMEGFQILT LEDVVSEADI FVTTTGNKDI IMVDHMRKMK NNAIVCNIGH FDNEIDMLGL
     ENYPGVKRIT IKPQTDRFVF PETNTGIIVL AEGRLMKLGC ATGHPSFVMS CSFTNQVIAQ
     LELWNERASG KYEKKVYVLP KHLDEKVAAL HLGKLGAKLT KLSKDQADYI SVPVEGPYKP
     AHYRY
//