Dipeptide epimerase with a broad substrate specificity. Catalyzes the epimerization of L-Ala-L-Ala, L-Ala-L-Ser, L-Ala-L-Thr, L-Ala-L-Met, L-Ala-L-Phe, L-Ala-L-Tyr, L-Gly-L-Asp, L-Val-L-Asp, L-Val-L-Glu and L-Val-L-Phe (in vitro). Can also catalyze the epimerization of L-Ala-L-Glu, but with lower efficiency. Binds 1 Mg(2+) ion per subunit. 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.