L-Ala-D/L-Glu epimerase catalyzes the epimerization of L-Ala-D/L-Glu and other dipeptides. The genomic context and the substrate specificity of characterized members of this family from E.coli and B.subtilis indicates a possible role in the metabolism of the murein peptide of peptidoglycan, of which L-Ala-D-Glu is a component. L-Ala-D/L-Glu epimerase is a member of the enolase-superfamily, which is characterized by the presence of an enolate anion intermediate which is generated by abstraction of the alpha-proton of the carboxylate substrate by an active site residue and is stabilized by coordination to the essential Mg2+ ion.