Involved in muropeptide degradation. Catalyzes the hydrolysis of the gamma-D-glutamyl-diaminopimelic acid (gamma-D-Glu-Dap) amide bond in the murein tripeptide L-alanyl-gamma-D-glutamyl-meso-diaminopimelic acid, leading to the formation of L-Ala-gamma-D-Glu and Dap. Has weak activity with L-Ala-gamma-D-Glu-L-Lys, MurNAc-tripeptide and gamma-D-Glu-meso-Dap. Cannot hydrolyze murein tetrapeptide. H2O + L-alanyl-gamma-D-glutamyl-meso-diaminoheptanedioate = L-alanyl-D-glutamate + meso-2,6-diaminoheptanedioate Binds 1 zinc ion per subunit. Cell wall degradation; peptidoglycan degradation. Homodimer. Belongs to the peptidase M14 family.