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ENZYME

ENZYME entry: EC 2.5.1.45

Accepted Name
homospermidine synthase (spermidine-specific)
Reaction catalysed
putrescine + spermidine <=> propane-1,3-diamine + sym-homospermidine
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_SENVEQ9M4B0, HSS1_SENVUP60038, HSS2_SENVE

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All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.5.1.-
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