Catalyzes the hydrolysis of N-succinyl-L,L-diaminopimelic acid (SDAP), forming succinate and LL-2,6-diaminoheptanedioate (DAP), an intermediate involved in the bacterial biosynthesis of lysine and meso-diaminopimelic acid, an essential component of bacterial cell walls. Can also hydrolyze all N-terminal Asp dipeptides except Asp-Pro. Asp-Ser is the best substrate, followed by Asp-Gly, Asp-Leu, and Asp-Cys. H2O + N-succinyl-(2S,6S)-2,6-diaminoheptanedioate = (2S,6S)-2,6-diaminoheptanedioate + succinate Binds 2 divalent cations per subunit, one with high affinity and the other with lower affinity. Zn(2+) and/or Co(2+) ions are used for desuccinylase activity. The form of DapE active as a peptidase contains Zn(2+) in the high-affinity site and Mn(2+) in the low-affinity site. Mn(2+)-activated peptidase is inhibited by Mn(2+) at concentration above 1 mM and by increasing concnentrations of Co(2+). There is a competitive inhibitor effect between the substrates. Hydrolysis of Asp-Leu by Mn(2+)-activated DapE is inhibited by SDAP, and hydrolysis of SDAP by Co(2+)-activated DapE is inhibited by Asp-Ser. Amino-acid biosynthesis; L-lysine biosynthesis via DAP pathway; LL-2,6-diaminopimelate from (S)-tetrahydrodipicolinate (succinylase route): step 3/3. Homodimer. Zn(+2) is usually found in the tight binding site, but the nature of the second cation in the low affinity binding site is different according the activity. Belongs to the peptidase M20A family. DapE subfamily.