N-acetylmuramyl-L-alanine amidase involved in innate immunity by degrading bacterial peptidoglycans (PGN). Probably plays a scavenger role by digesting biologically active PGN into biologically inactive fragments. Has no direct bacteriolytic activity (By similarity). Hydrolyzes the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell-wall glycopeptides. Constitutively expressed at high level in gut, in addition to the induced expression in fat body. 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.