Home  |  Contact

ENZYME entry: EC 2.5.1.45

Accepted Name
Homospermidine synthase (spermidine-specific).
Reaction catalysed
Spermidine + putrescine <=> sym-homospermidine + propane-1,3-diamine
Cofactor(s)
NAD(+).
Comment(s)
  • A eukaryotic enzyme found in plants.
  • The reaction occurs in three steps, with some of the intermediates presumably remaining enzyme-bound: (1) NAD(+)-dependent dehydrogenation of spermidine to dehydrospermidine. (2) Attack by water forming 4-aminobutanal (and releasing propane- 1,3-diamine). (3) Condensation of 4-aminobutanal with purescine, which forms homospermidine and restores NAD(+).
  • This enzyme is more specific than EC 2.5.1.44, which is found in bacteria, as it cannot use putrescine as donor of the 4-aminobutyl group.
  • Forms part of the biosynthetic pathway of the poisonous pyrrolizidine alkaloids of the ragworts (Senecio).
Cross-references
BRENDA2.5.1.45
EC2PDB2.5.1.45
ExplorEnz2.5.1.45
PRIAM enzyme-specific profiles2.5.1.45
KEGG Ligand Database for Enzyme Nomenclature2.5.1.45
IUBMB Enzyme Nomenclature2.5.1.45
IntEnz2.5.1.45
MEDLINEFind literature relating to 2.5.1.45
MetaCyc2.5.1.45
Rhea expert-curated reactions2.5.1.45
UniProtKB/Swiss-Prot
Q9SC13, HSS1_SENVE;  Q9M4B0, HSS1_SENVU;  P60038, HSS2_SENVE;  

View entry in original ENZYME format
View entry in raw text format (no links)
All UniProtKB/Swiss-Prot entries referenced in this entry, with possibility to download in different formats, align etc.
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.5.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.5.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.-.-.-