Peptidoglycan-recognition protein that plays a key role in innate immunity by binding to peptidoglycans (PGN) of Gram-positive bacteria and activating the Toll pathway upstream of spz activating enzyme SPE (PubMed:11106397, PubMed:16399077, PubMed:15448690). Has no activity against Gram-negative bacteria and fungi (PubMed:11742401). Shows some partial redundancy with PRPGP-SD in Gram-positive bacteria recognition (PubMed:11742401, PubMed:15448690). May act by forming a complex with GNBP1 that activates the proteolytic cleavage of Spatzle and the subsequent activation of Toll pathway (PubMed:14684822, PubMed:14722090, PubMed:11742401). Binds to diaminopimelic acid-type tetrapeptide PGN (DAP-type PGN) and lysine-type PGN (Lys-type PGN) (PubMed:15361936). Has some L,D-carboxypeptidase activity for DAP-type PGN, which are specific to prokaryotes, but not for Lys-type PGN (PubMed:15361936). H2O + N-acetyl-D-glucosaminyl-N-acetylmuramoyl-L-alanyl-D-glutamyl-6-carboxy-L-lysyl-D-alanine = D-alanine + N-acetyl-D-glucosaminyl-N-acetylmuramoyl-L-alanyl-D-glutamyl-6-carboxy-L-lysyl Secreted in hemolymph. In larvae, it is expressed in fat body. Also expressed in uninduced hemocytes and mbn-2 cells. Strongly up-regulated by PGN from B.subtilis. Regulated by both imd/Relish and Toll pathways. Belongs to the N-acetylmuramoyl-L-alanine amidase 2 family. Although suggested, the interaction with GNBP1 has not been experimentally demonstrated.