The reaction takes place in the opposite direction. Part of a bacterial polyamine biosynthesis pathway. L-aspartate 4-semialdehyde and propane-1,3-diamine/putrescine form a Schiff base that is reduced to form carboxynorspermidine/carboxyspermidine, respectively [1]. The enzyme from the bacterium Vibrio cholerae is essential for biofilm formation [2]. The enzyme from Campylobacter jejuni only produces carboxyspermidine in vivo even though it also can produce carboxynorspermidine in vitro [3].
