Aspartate—ammonia ligase

In enzymology, an aspartate—ammonia ligase is an enzyme that catalyzes the chemical reaction


 * ATP + L-aspartate + NH3 $$\rightleftharpoons$$ AMP + diphosphate + L-asparagine

The 3 substrates of this enzyme are ATP, L-aspartate, and NH3, whereas its 3 products are AMP, diphosphate, and L-asparagine.

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-aspartate:ammonia ligase (AMP-forming). Other names in common use include asparagine synthetase, and L-asparagine synthetase. This enzyme participates in 3 metabolic pathways: alanine and aspartate metabolism, cyanoamino acid metabolism, and nitrogen metabolism.

Structural studies
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and.