Catalyzes the epimerization of L-Ala-D-Glu to L-Ala-L-Glu and may play a role in the metabolism of the murein peptide, of which L-Ala-D-Glu is a component. Is also able to catalyze the epimerization of L-Ala-D-Asp, L-Ala-L-Glu, L-Ala-L-Ser, L-Ala-L-Pro, L-Ala-L-L-Val, L-Ala-L-Thr, L-Ala-L-Leu, L-Ala-L-Ile and L-Gly-L-Glu (in vitro). L-alanyl-L-glutamate = L-alanyl-D-glutamate Binds 1 Mg(2+) ion per subunit. kcat is 147 sec(-1) for epimerization of L-Ala-L-Glu. kcat is 59 sec(-1) for epimerization of L-Ala-D-Glu. kcat is 96 sec(-1) for epimerization of L-Val-L-Glu. kcat is 43 sec(-1) for epimerization of L-Val-D-Glu. kcat is 30 sec(-1) for epimerization of L-Ile-L-Glu. Part of a large, functionally divergent protein family. Protein modeling and substrate docking were used to predict the substrate specificity, prior to biochemical analysis. Belongs to the mandelate racemase/muconate lactonizing enzyme family.