Thermospermine synthase (EC 2.5.1.79, TSPMS, ACL5 (ACAULIS5), SAC51) is an enzyme with systematic name S-adenosylmethioninamine:spermidine 3-aminopropyltransferase (thermospermine synthesizing).
[1][2][3] This enzyme catalyses the following chemical reaction This enzyme is required for correct xylem specification through regulation of the lifetime of the xylem elements.