Spermidine Synthase

**Definition:** An enzyme that catalyzes the transfer of the propylamine moiety from 5'-deoxy-5'-S-(3-methylthiopropylamine)sulfonium adenosine to putrescine in the biosynthesis of spermidine. The enzyme has a molecular weight of approximately 73,000 kDa and is composed of two subunits of equal size.

**Tree numbers:** - D08.811.913.225.825

**Synonyms:** - Aminopropyltransferase - Propylamine Transferase - Putrescine Aminopropyltransferase - Spermidine Synthetase