MGP Database

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MGP002978

UniProt Annotations

Entry Information
Gene Namespermidine synthase
Protein EntrySPEE_HUMAN
UniProt IDP19623
SpeciesHuman
Comments
Comment typeDescription
Biophysicochemical PropertiesKinetic parameters: KM=20 uM for putrescine {ECO:0000269|PubMed:17585781}; KM=0.9 uM for S-adenosylmethioninamine {ECO:0000269|PubMed:17585781};
Catalytic ActivityS-adenosyl 3-(methylthio)propylamine + putrescine = 5'-S-methyl-5'-thioadenosine + spermidine. {ECO:0000269|PubMed:17585781}.
Enzyme RegulationThe activity is thought to be regulated mainly by the availability of decarboxylated S-adenosylmethionine.
FunctionCatalyzes the production of spermidine from putrescine and decarboxylated S-adenosylmethionine (dcSAM). Has a strong preference for putrescine as substrate, and has very low activity towards 1,3-diaminopropane. Has extremely low activity towards spermidine. {ECO:0000269|PubMed:17585781}.
PathwayAmine and polyamine biosynthesis; spermidine biosynthesis; spermidine from putrescine: step 1/1.
SimilarityBelongs to the spermidine/spermine synthase family. {ECO:0000305}.
SimilarityContains 1 PABS (polyamine biosynthesis) domain. {ECO:0000305}.
SubunitHomodimer or homotetramer. {ECO:0000269|PubMed:17585781}.
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