spermidine synthase; aminopropyltransferase; putrescine aminopropyltransferase; spermidine synthetase; SpeE (ambiguous); S-adenosylmethioninamine:putrescine 3-aminopropyltransferase; S-adenosyl 3-(methylthio)propylamine:putrescine 3-aminopropyltrans • • •