| Domain | Name | Category | Type |
| IPR001045 | Spermidine/spermine synthases | Family | Family |
| IPR029063 | S-adenosyl-L-methionine-dependent methyltransferase | Family | Homologous superfamily |
| IPR030373 | Polyamine biosynthesis domain, conserved site | Site | Conserved site |
| IPR030374 | Polyamine biosynthesis domain | Domain | Domain |
| IPR030668 | Spermidine/spermine synthase, eukaryotes | Family | Family |
| IPR035246 | Spermidine synthase, tetramerisation domain | Domain | Domain |
| IPR037163 | Spermidine synthase, tetramerisation domain superfamily | Family | Homologous superfamily |