In enzymology, a glutamate-putrescine ligase (EC 6.3.1.11) is an enzyme that catalyzes the chemical reaction

ATP + L-glutamate + putrescine ${\displaystyle \rightleftharpoons }$ ADP + phosphate + gamma-L-glutamylputrescine

The 3 substrates of this enzyme are ATP, L-glutamate, and putrescine, whereas its 3 products are ADP, phosphate, and gamma-L-glutamylputrescine.

This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds as acid-D-ammonia (or amine) ligases (amide synthases). The systematic name of this enzyme class is L-glutamate:putrescine ligase (ADP-forming). Other names in common use include gamma-glutamylputrescine synthetase, and YcjK. This enzyme participates in urea cycle and metabolism of amino groups.

• Kurihara S, Oda S, Kato K, Kim HG, Koyanagi T, Kumagai H, Suzuki H (2005). "A novel putrescine utilization pathway involves gamma-glutamylated intermediates of Escherichia coli K-12". J. Biol. Chem. 280 (6): 4602–8. doi:10.1074/jbc.M411114200. PMID 15590624.