Spermine synthase

Spermine synthase (EC 2.5.1.22, spermidine aminopropyltransferase, spermine synthetase) is an enzyme that converts spermidine into spermine.^[1][2] This enzyme catalyses the following chemical reaction

S-adenosylmethioninamine + spermidine ${\displaystyle \rightleftharpoons }$ S-methyl-5'-thioadenosine + spermine

Spermine synthase
Identifiers
EC no.	2.5.1.22
CAS no.	74812-43-4
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

Spermine synthase is an enzyme involved in polyamine biosynthesis. It is present in all eukaryotes and plays a role in a variety of biological functions in plants^[3] Its structure consists of two identical monomers of 41 kDa with three domains each, creating a homodimer formed via dimerization. The interactions between one of the three domains, the N-terminals of the monomers, is responsible for dimerization as that is where the active site is located; the central terminal consisting of four β- strands structurally forming a lid for the third domain, the C-terminal domain.^[4]