Spermidine is numbered so that atom N-1 is in the amino group of the aminopropyl part of the molecule. The enzyme from Escherichia coli is bifunctional and also catalyses the glutathionylspermidine synthase (EC 6.3.1.8) reaction, resulting in a net hydrolysis of ATP.
Glutathionylspermidine metabolism in Escherichia coli. Purification, cloning, overproduction, and characterization of a bifunctional glutathionylspermidine synthetase/amidase.