S-adenosyl 3-(methylsulfanyl)propylamine + propane-1,3-diamine => norspermidine + S-methyl-5'-thioadenosine + H(+)
s-adenosyl 3-(methylsulfanyl)propylamine + propane-1,3-diamine => norspermidine + s-methyl-5'-thioadenosine + h(+)