This enzyme catalyzes carboxypeptidation and transpeptidation reactions involved in bacterial cell wall metabolism. It effectively catalyzes the transfer of the N-alpha, N-epsilon-diacetyl-L-lysyl-D-alanyl electrophilic group of the standard tripeptide substrate N-alpha,N-epsilon-diacetyl-L-lysyl-D-alanyl-D-alanine to water. It also performs a weak beta-lactamase activity, hydrolyzing penicillin into penicilloate at a very low rate. Cleavage of the bond: (Ac)2-L-lysyl-D-alanyl-|-D-alanine. Binds 1 zinc ion per subunit. The N-terminus is partially blocked as a result of the cyclization of the first two amino acids into anhydroaspartylglycine imide. Belongs to the peptidase M15 family.