In enzymology, a D-alanine gamma-glutamyltransferase is an enzyme that catalyzes the chemical reaction L-glutamine + D-alanine ⇌ {\displaystyle \rightleftharpoons } NH3 + gamma-L-glutamyl-D-alanineThus, the two substrates of this enzyme are L-glutamine and D-alanine, whereas its two products are NH3 and gamma-L-glutamyl-D-alanine. Wikipedia