In enzymology, a glutamin-(asparagin-)ase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are L-glutamine and H<sub>2</sub>O, whereas its two products are L-glutamate and NH<sub>3</sub>.
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is L-glutamine(L-asparagine) amidohydrolase. This enzyme participates in 4 metabolic pathways: glutamate metabolism, alanine and aspartate metabolism, d-glutamine and d-glutamate metabolism, and nitrogen metabolism.
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes , , and .