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 |
BRENDA | 2.5.1.45 |
EC2PDB | 2.5.1.45 |
ExplorEnz | 2.5.1.45 |
PRIAM enzyme-specific profiles | 2.5.1.45 |
KEGG Ligand Database for Enzyme Nomenclature | 2.5.1.45 |
IUBMB Enzyme Nomenclature | 2.5.1.45 |
IntEnz | 2.5.1.45 |
MEDLINE | Find literature relating to 2.5.1.45 |
MetaCyc | 2.5.1.45 |
Rhea expert-curated reactions | 2.5.1.45 |
UniProtKB/Swiss-Prot |
|
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ENZYME /
UniProtKB/Swiss-Prot entries corresponding to 2.5.1.-
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