In enzymology, an aspartate ammonia-lyase (EC 18.104.22.168) is an enzyme that catalyzes the chemical reaction
fumarate + NH3
Hence, this enzyme has one substrate, L-aspartate, and two products, fumarate and NH3.
This enzyme belongs to the family of lyases, specifically ammonia lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is L-aspartate ammonia-lyase (fumarate-forming). Other names in common use include aspartase, fumaric aminase, L-aspartase, and L-aspartate ammonia-lyase. This enzyme participates in alanine and aspartate metabolism and nitrogen metabolism.
Aspartate ammonia-lyase Wikipedia
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 1J3U and 1JSW.