ID   2.5.1.44
DE   homospermidine synthase.
CA   (1) 2 putrescine = NH4(+) + sym-homospermidine.
CA   (2) putrescine + spermidine = propane-1,3-diamine + sym-homospermidine.
CC   -!- The reaction of this bacterial enzyme occurs in three steps, with
CC       some of the intermediates presumably remaining enzyme-bound:
CC       (1) NAD(+)-dependent dehydrogenation of either putrescine or
CC       spermidine.
CC       (2) Attack by water forming 4-aminobutanal (and releasing ammonia or
CC       propane-1,3-diamine, respectively).
CC       (3) Condensation of 4-aminobutanal with putrescine, which forms
CC       homospermidine and restores NAD(+).
CC   -!- Differs from the eukaryotic enzyme EC 2.5.1.45, which cannot use
CC       putrescine as donor of the aminobutyl group.
DR   O32323, HSS_BLAVI  ;  Q98H64, HSS_RHILO  ;
//