Glutathionylspermidine synthase () is an enzyme characterised from Crithidia fasciculata and Escherichia coli that catalyzes the amidation of glutathione with spermidine to give glutathionylspermidine:
The enzyme is bifunctional and in the reverse direction is equivalent to glutathionylspermidine amidase, which hydrolyses the product back to the starting materials.
This enzyme is a ligase, specifically one forming carbon-nitrogen bonds as acid-D-ammonia (or amine) ligases (amide synthases). The systematic name of this enzyme class is gamma-L-glutamyl-L-cysteinyl-glycine:spermidine ligase (ADP-forming) [spermidine is numbered so that atom N-1 is in the amino group of the aminopropyl part of the molecule]. This enzyme is also called glutathione:spermidine ligase (ADP-forming). This enzyme participates in glutathione metabolism. It uses magnesium as a cofactor.
Structural studies As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes , , , , and .
References