Spermine synthase
From Wikipedia, the free encyclopedia
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
| Spermine synthase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 2.5.1.22 | ||||||||
| CAS no. | 74812-43-4 | ||||||||
| Databases | |||||||||
| BRENDA | enzyme data | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | enzyme entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| Rhea | reactions | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| |||||||||
Spermine synthase is an enzyme involved in polyamine biosynthesis. In humans, it is coded by SMS (gene), but 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]
Function
The enzyme catalyses a reaction which transfers a three-carbon aminopropyl unit to spermidine. The source is S-adenosylmethioninamine:[4]
The reaction is similar to one which produces spermidine from putrescine by action of spermidine synthase.[5]
